|This article is part of a series on:|
|Beliefs and practices|
Succession to Muhammad
Imamate of the Family
Mourning of Muharram
Intercession · Ismah
The Occultation · Clergy
|The Qur'an · Sahaba
|Ashura · Arba'een · Mawlid
Eid ul-Fitr · Eid al-Adha
· Ismāʿīlī · Zaidi
The verse of purification
Mubahala · Two things
Khumm · Fatimah's house
First Fitna · Second Fitna
The Battle of Karbala
|Muhammad · Ali · Fatimah
Hasan · Hussein
|List of Shia companions|
|Fatimah · Khadijah · Zaynab bint Ali · Fatimah bint al-Hasan · Sukayna bint Husayn · Rubab · Shahrbanu · Nijmah · Fātimah bint Mūsā · Hakimah Khātūn · Narjis · Fatimah bint Asad · Farwah bint al-Qasim ·|
Sunni and Shia Islam are the two major denominations of Islam. The demographic breakdown between the two denominations is difficult to assess and varies by source, but a good approximation is that 75–90% of the world's Muslims are Sunni and 10–20% are Shia, with most Shias belonging to the Twelver tradition and the rest divided between several other groups.
Sunnis are a majority in most Muslim communities: in South East Asia, China, South Asia, Africa, and most of the Arab world. Shia make up the majority of the population in Iran, Iraq, Lebanon, Azerbaijan, and Bahrain (all together called the Shia Crescent), while Pakistan has the second-largest Shia Muslim (Twelver) population in the world.
The historic background of the Sunni–Shia split lies in the schism that occurred when the Islamic prophet Muhammad died in the year 632, leading to a dispute over succession to Muhammad as a caliph of the Islamic community spread across various parts of the world which led to the Battle of Siffin. Sectarian violence persists to this day from Pakistan to Yemen and is a major element of friction throughout the Middle East.
Over the years, Sunni–Shia relations have been marked by both cooperation and conflict. Tensions between communities can intensify during power struggles, such as the Bahraini uprising, Syrian civil war or the 2003 Iraq War. Today there are differences in religious practice, traditions and customs, often related to jurisprudence. Although all Muslim groups consider the Quran to be divine, Sunni and Shia have different opinions on hadith.
Sunnis are a majority in most Muslim communities in Southeast Asia, China, South Asia, Africa, most of the Arab World, and among Muslims in the United States (of which 85-90% are Sunnis). Shias make up the majority of the Muslim population in Iran (around 90–95%), Azerbaijan (around 85%), Iraq (around 60-65%) and Bahrain (around 65%). Minority Shia communities are also found in Yemen, around 30% of the Muslim population (mostly of the Zaydi sect), and about 10-15% of Turkey are of the Alevi sect. The Shia constitute around 20% of Kuwait, 45-55% of the Muslim population in Lebanon, 10% of Saudi Arabia, 15% of Syria, and 10-15% of Pakistan. Around 10-15% of Afghanistan, less than 5% of the Muslims in Nigeria, and around 3% of population of Tajikistan are Shia.
...Shias are about 10-to-15 percent of the entire Muslim world. We don't have accurate statistics because in much of the Middle East it is not convenient to have them, for ruling regimes in particular. But the estimates are that they are about 10-to-15 percent of the Muslim world, which puts them somewhere between 165-to-190 million people....The overwhelming majority of that population lives between Pakistan and Lebanon. Iran always had been a Shia country, the largest one, with about 60 million population. Pakistan is the second-largest Shia country in the world, with about 30 million population. And, potentially, there are as many Shias in India as there are in Iraq.—Vali Nasr, October 18, 2006
Differences in beliefs and practices 
Historical beliefs and leadership 
Successors of Muhammad 
Sunnis believe that Abu Bakr, the father of Muhammad's wife Aisha, was Muhammad's rightful successor and that the method of choosing or electing leaders (Shura) endorsed by the Quran is the consensus of the Ummah, (the Muslim community).
Shiites believe that Muhammad divinely ordained his cousin and son-in-law Ali (the father of his grandsons Hasan ibn Ali and Hussein ibn Ali) in accordance with the command of God to be the next caliph making Ali and his direct descendants Muhammad's successors. Ali was married to Fatimah, Muhammad's daughter.
Muhammad's wife Aisha endorsed her father Abu Bakr as the successor to Muhammad. In the Battle of the Camel (656), Aisha opposed her step son-in-law Ali outside the city of Basra because she wanted justice on the perpetrators of the assassination of the previous caliph, Uthman. Aisha's forces were defeated and Muhammad's widow was respectfully escorted back to Medina. Sunnis follow the Rashidun "rightly guided Caliphs", who were the first four caliphs who ruled after the death of Muhammad: Abu Bakr (632-634), Umar ibn al-Khattab (634-644), Usman ibn Affan (644-656), and Ali Ibn Abi Talib (656-661).
Shia theology discounts the legitimacy of the first three caliphs and believe that Ali is the second-most divinely inspired man (after Muhammed) and that he and his descendants by Muhammad's daughter Fatimah daughter of Muhammad's wife Khadijah bint Khuwaylid, the Imams, are the sole legitimate Islamic leaders.
The Imamate of the Shia encompasses far more of a prophetic function than the Caliphate of the Sunnis. Unlike Sunni, Shias believe special spiritual qualities have been granted not only to Muhammad but also to Ali and the other Imams. Twelvers believe the imams are immaculate from sin and human error (ma'sūm), and can understand and interpret the hidden inner meaning of the teachings of Islam. In this way the Imams are trustees (wasi) who bear the light of Muhammad (Nūr Muhammadin).
While Shias and Sunnis differ on the nature of the Mahdi, many members of both groups, especially Sufis, believe that the Mahdi will appear at end times to bring about a perfect and just Islamic society.
In Shia Islam "the Mahdi symbol has developed into a powerful and central religious idea." Twelvers believe the Mahdi will be Muhammad al-Mahdi, the twelfth Imam returned from the Occultation, where he has been hidden by God since 874. In contrast, mainstream Sunnis believe the Mahdi will be named Muhammad, be a descendant of Muhammad, and will revive the faith, but will not necessarily be connected with the end of the world. But there is nothing in the Quran referring to a Mahdi.
The Shias accept some of the same hadiths used by Sunnis as part of the sunnah to argue their case. In addition, they consider the sayings of Ahl al-Bayt that are not attributed directly to Muhammad as hadiths. Shias do not accept many Sunni hadiths unless they are also recorded in Shia sources or the methodology can be proven of how they were recorded. Also, some Sunni-accepted hadith are less favored by Shias; one example is that because of Aisha's opposition to Ali, hadith narrated by Aishah are not given the same authority as those by other companions. Another example is hadith narrated by Abu Hurairah, who is considered by Shias as the enemy of Ali. The Shia argument is that Abu Hurairah was only a Muslim four years of his life before Muhammad's death. Although he accompanied Muhammad for four years only, he managed to record ten times as many hadiths as Abu Bakr and Ali each.
Shiism and Sufism 
Shiism and Sunni Sufism are said to share a number of hallmarks: Belief in an inner meaning to the Quran, special status for some mortals (saints for Sufi, Imams for Shias), as well as veneration of Ali and Muhammad's family.
Many distinctions can be made between Sunnis and Shiaīs through observation alone:
When prostrating during ritual prayer (Salah), Shias place their forehead onto a piece of naturally occurring material, often a clay tablet (mohr), soil (turbah) or at times sand from Karbala, the place where Hussein ibn Ali was martyred, instead of directly onto a prayer rug. There is precedence for this in Sunni thought, as it is recommended not to prostrate on a non-natural surface.
Some Shia perform prayers back to back, sometimes worshipping two times consecutively (1+2+2 i.e. fajr on its own Dhuhr with Asr and Maghrib with Isha'), thus praying five times a day but with a very small break in between the prayer, a tradition Muhammad followed according the Sunni scholar Muhammad al-Bukhari and which is also followed by Muslims all over the world while performing Hajj, instead of five prayers with at least one hour gap between them as required by Sunni schools of law.
Shias and the followers of the Sunni Maliki school hold their hands at their sides during prayer; Sunnis of other schools cross their arms (right over left) and clasp their hands, although it is commonly held by Sunni scholars that either is acceptable.
The Twelved Shia permit Nikah mut‘ah—fixed-term temporary marriage—,which is not acceptable within the Sunni community or the Ismaili Shia or the Zaidi Shia and is believed a planned and agreed fornication. Mutah is not the same as Misyar marriage or 'Arfi marriage, which has no date of expiration and is permitted by some Sunnis. A Misyar marriage differs from a conventional Islamic marriage in that the man does not have financial responsibility over the woman by her own free will. The man can divorce the woman whenever he wants to in a Misyar marriage.
Hijab and dress 
Both Sunni and Shia women wear the hijab. Devout women of the Shia traditionally wear black as do some Sunni women in the Gulf. Some Shia religious leaders also wear a black robe. Mainstream Shia and Sunni women wear the hijab differently. Some Sunni scholars emphasize covering of all body including the face in public whereas some scholars exclude the face from hijab. Shias believe that the hijab must cover around the perimeter of the face and up to the chin. Some Shia women, such as those in Iran and Iraq, use their hand to hold the black chador, in order to cover their faces when in public as Sunnis.
Given names 
Shia are often recognizable by their names, which are often derived from the proper names or titles of saints. In particular, the names Ali, Hussein, and Hasan are disproportionately common among Shias, though they may also be used by Sunnis. Shias who trace their ancestry back to Muhammad through his daughter Fatimah carry the title Sayyid. Umar and Uthman, being the names of caliphs recognized by Sunnis but not Shias, are commonly used as names for Sunnis but are rare for Shias.
Sunni theology 
The Five Pillars of Islam (Arabic: أركان الإسلام) is the term given to the five duties incumbent on every Muslim. These duties are Shahada (profession of faith), Salah (prayers), Zakāt (giving of alms), Sawm (fasting, specifically during Ramadan) and Hajj (pilgrimage to Mecca). These five practices are essential to Sunni Muslims.
Shia theology 
The Five Pillars are also accepted as essential rituals and practiced by Shias. Shia theology has two concepts that define religion as a whole. There are Roots of Religion (Usūl al-Dīn) and Branches of Religion (Furu al Din).
Abbasid era 
The Umayyads were overthrown in 750 by a new dynasty, the Abbasids. The first Abbasid caliph, As-Saffah, recruited Shia support in his campaign against the Umayyads by emphasizing his blood relationship to Muhammad's household through descent from his uncle, ‘Abbas ibn ‘Abd al-Muttalib. The Shia also believe that he promised them that the Caliphate, or at least religious authority, would be vested in the Shia Imam. As-Saffah assumed both the temporal and religious mantle of Caliph himself. He continued the Umayyad dynastic practice of succession, and his brother al-Mansur succeeded him in 754.
Ja'far al-Sadiq, the sixth Shia Imam, died during al-Mansur's reign, and there were claims that he was murdered on the orders of the caliph. (However, Abbasid persecution of Islamic lawyers was not restricted to the Shia. Abū Ḥanīfa, for example was imprisoned by al-Mansur and tortured.)
Shia sources further claim that by the orders of the tenth Abassid caliph, al-Mutawakkil, the tomb of the third Imam, Hussein ibn Ali in Karbala, was completely demolished, and Shias were sometimes beheaded in groups, buried alive, or even placed alive within the walls of government buildings still under construction.
The Shia believe that their community continued to live for the most part in hiding and followed their religious life secretly without external manifestations.
Shia–Sunni in Iraq 
Many Shia Iranians migrated to what is now Iraq in the 16th century. "It is said that when modern Iraq was formed, 75% of the population of Karbala was Iranian". In time, these immigrants adopted the Arabic language and Arab identity, but their origin has been used to "unfairly cast them as lackeys of Iran". Other Iraqi Shias are ethnic Arabs with roots in Iraq as deep as those of their Sunni counterparts.
Shia–Sunni in Persia 
Shafi'i Sunnism was the dominant form of Islam in most of Iran until rise of the Safavid Empire although a significant undercurrent of Ismailism and a very large minority of Twelvers were present all over Persia. Many illustrious scholars and scientists who lived before the Safavid era, such as Avicenna, Jābir ibn Hayyān, Alhazen, Al-Farabi, Ferdowsi and Nasir al-Din al-Tusi and the poet Hafez were Shia Muslims of both the Ismaili and Twelver traditions (some indistinguishably so, such as al-Tusi), as was most of Iran's elite. There were many Sunni scientists and scholars as well, such as Fakhr al-Din al-Razi, philosopher-theologian Al-Ghazali, and poet Saadii
Nezamiyehs were the medieval institutions of Islamic higher education established by Nizam al-Mulk in the 11th century. Nizamiyyah institutes were the first well-organized universities in the Muslim world. The most famous and celebrated of all the nizamiyyah schools was Al-Nizamiyya of Baghdad (established 1065), where Nizam al-Mulk appointed the distinguished philosopher and theologian, Ghazali, as a professor. Other Nizamiyyah schools were located in Nishapur, Balkh, Herat and Isfahan.
The majority of Iranians turned to Shi'ism from the Safawid period onwards. Of course, it cannot be denied that Iran's environment was more favourable to the flourishing of the Shi'ism as compared to all other parts of the Muslim world. Shi'ism did not penetrate any land to the extent that it gradually could in Iran. With the passage of time, Iranians' readiness to practise Shi'ism grew day by day. Had Shi`ism not been deeply rooted in the Iranian spirit, the Safawids (907-1145/ 1501-1732) would not have succeeded in converting Iranians to the Shi'a creed and making them follow the Prophet's Ahl al-Bayt sheerly by capturing political power.
The Shia in Persia before the Safavids 
The domination of the Sunni creed during the first nine Islamic centuries characterizes the religious history of Iran during this period. There were however some exceptions to this general domination which emerged in the form of the Zaydis of Tabaristan, the Buwayhid, the rule of the Sultan Muhammad Khudabandah (r. 1304-1316) and the Sarbedaran. Nevertheless, apart from this domination there existed, firstly, throughout these nine centuries, Shia inclinations among many Sunnis of this land and, secondly, Twelver and Zaidi Shiism had prevalence in some parts of Iran. During this period, the Shia in Iran were nourished from Kufa, Baghdad and later from Najaf and Al Hillah. Shia were dominant in Tabaristan, Qom, Kashan, Avaj and Sabzevar. In many other areas the population of Shias and Sunni was mixed.
The first Zaidi state was established in Daylaman and Tabaristan (northern Iran) in 864 by the Alavids; it lasted until the death of its leader at the hand of the Samanids in 928. Roughly forty years later the state was revived in Gilan (north-western Iran) and survived under Hasanid leaders until 1126. After which from the 12th-13th centuries, the Zaidis of Daylaman, Gilan and Tabaristan then acknowledge the Zaidi Imams of Yemen or rival Zaidi Imams within Iran.
The Buyids, who were Zaidi and had a significant influence not only in the provinces of Persia but also in the capital of the caliphate in Baghdad, and even upon the caliph himself, provided a unique opportunity for the spread and diffusion of Shia thought. This spread of Shiism to the inner circles of the government enabled the Shia to withstand those who opposed them by relying upon the power of the caliphate.
Twelvers came to Iran from Arab regions in the course of four stages. First, through the Asharis tribe at the end of the 7th and during the 8th century. Second through the pupils of Sabzevar, and especially those of Al-Shaykh Al-Mufid, who were from Rey and Sabzawar and resided in those cities. Third, through the school of Hillah under the leadership of Al-Hilli and his son Fakhr al-Muhaqqiqin. Fourth, through the scholars of Jabal Amel residing in that region, or in Iraq, during the 16th and 17th centuries who later migrated to Iran.
On the other hand, the Ismaili da‘wah ("missionary institution") sent missionaries (du‘āt, sg. dā‘ī) during the Fatimid Caliphate to Persia. When the Ismailis divided into two sects, Nizaris established their base in northern Persia. Hassan-i Sabbah conquered fortresses and captured Alamut in 1090. Nizaris used this fortress until the Mongols finally seized and destroyed it in 1256.
After the Mongols and the fall of the Abbasids, the Sunni Ulama suffered greatly. In addition to the destruction of the caliphate there was no official Sunni school of law. Many libraries and madrasahs were destroyed and Sunni scholars migrated to other Islamic areas such as Anatolia and Egypt. In contrast, most Shia were largely unaffected as their center was not in Iran at this time. For the first time, the Shia could openly convert other Muslims to their movement.
Several local Shia dynasties like the Marashi and Sarbadars were established during this time. The kings of the Aq Qoyunlu and Kara Koyunlu dynasties ruled in Tabriz with a domain extending to Fars and Kerman. In Egypt the Fatimid government ruled.
Muhammad Khudabandah, the famous builder of Soltaniyeh, was among the first of the Mongols to convert to Shiaism, and his descendants ruled for many years in Persia and were instrumental in spreading Shī‘ī thought. Sufism played a major role in spread of Shiism in this time.
After the Mongol invasion Shiims and Sufism once again formed a close association in many ways. Some of the Ismailis whose power had broken by the Mongols, went underground and appeared later within Sufi orders or as new branches of already existing orders. In Twelve-Imam Shiism, from the 13th to the 16th century, Sufism began to grow within official Shiite circles. The extremist sects of the Hurufis and Shasha'a grew directly out of a background that is both Shiite and Sufi. More important in the long run than these sects were the Sufi orders which spread in Persia at this time and aided in the preparing the ground for the Shiite movement of Safavids. Two of these orders are of particular significance in this question of the relation of Shiism and Sufism: The Nimatullahi order and Nurbakhshi order.
Shiism in Persia after Safavids 
Ismail I initiated a religious policy to recognize Shiism as the official religion of the Safavid Empire, and the fact that modern Iran remains an officially Shia state is a direct result of Ismail's actions.
Unfortunately for Ismail, most of his subjects were Sunni. He thus had to enforce official Shiism violently, putting to death those who opposed him. Under this pressure, Safavid subjects either converted or pretended to convert, but it is safe to say that the majority of the population was probably genuinely Shia by the end of the Safavid period in the 18th century, and most Iranians today are Shia, although there is still a Sunni minority.
Immediately following the establishment of Safavid power the migration of scholars began and they were invited to Iran ... By the side of the immigration of scholars, Shi'i works and writings were also brought to Iran from Arabic-speaking lands, and they performed an important role in the religious development of Iran ... In fact, since the time of the leadership of Shaykh Mufid and Shaykh Tusi, Iraq had a central academic position for Shi'ism. This central position was transferred to Iran during the Safavid era for two-and-a-half centuries, after which it partly returned to Najaf. ... Before the Safavid era Shi'i manuscripts were mainly written in Iraq, with the establishment of the Safavid rule these manuscripts were transferred to Iran.
During the early days of the Iranian Revolution, Ayatollah Ruhollah Khomeini endeavored to bridge the gap between Shiites and Sunnis by declaring it permissible for Twelvers to pray behind Sunni imams and by forbidding criticizing the Caliphs who preceded Ali—an issue that had caused much animosity between the two groups.
Shia–Sunni in Levant 
Shias claim that despite these advances, many Shias in Syria continued to be killed during this period for their faith. One of these was Muhammad Ibn Makki, called Shahid-i Awwal (the First Martyr), one of the great figures in Shia jurisprudence, who was killed in Damascus in 1384.
Shia–Sunni in South Asia 
Shia in South Asia faced persecution by some Sunni rulers and Mughal Emperors which resulted in the killings of Shia scholars like Qazi Nurullah Shustari (also known as Shaheed-e-Thaalis, the third Martyr) and Mirza Muhammad Kamil Dehlavi (also known as Shaheed-e- Rabay, the fourth Martyr) who are two of the five martyrs of Shia Islam. Shias in Kashmir in subsequent years had to pass through the most atrocious period of their history. Plunder, loot and massacres which came to be known as Taarajs virtually devastated the community. History records 10 such Taarajs also known as Taraj-e-Shia between 15th to 19th century in 1548, 1585, 1635, 1686, 1719, 1741, 1762, 1801, 1830, 1872 during which the Shia habitations were plundered, people slaughtered, libraries burnt and their sacred sites desecrated.
Sunni–Shia clashes also occurred frequently in the 20th century in South Asia. There were many between 1904 and 1908 especially in the United Provinces (Uttar Pradesh) area. These clashes revolved around the public cursing of the first three caliphs by Shias and the praising of them by Sunnis. To put a stop to the violence public demonstrations were banned in 1909 on the three most sensitive days: Ashura, Chehlum and Ali's death on 21 Ramadan. Intercommunal violence resurfaced in 1935-6 and again in 1939 when many thousands of Sunni and Shias defied the ban on public demonstrations and took to the streets. Shia are estimated to be 21-35% of the Muslim population in South Asia, although the total number is difficult to estimate due to the intermingling between the two groups and practice of taqiyya by Shia 
Modern Sunni–Shia relations 
In addition to Iran, Iraq has emerged as a major Shia government when the Twelvers achieved political dominance in 2005 under American occupation. The two communities have often remained separate, mingling regularly only during the Hajj pilgrimage in Mecca. In some countries like Iraq, Syria and Bahrain, communities have mingled and intermarried. Some Shia have complained of mistreatment in countries dominated by Sunnis, especially in Saudi Arabia, while some Sunnis have complained of discrimination in the Twelver-dominated states of Iraq and Iran.
At least one scholar sees the period from the collapse of the Ottoman Empire through the decline of Arab nationalism as a time of relative unity and harmony between traditionalist Sunni and Shia Muslims—unity brought on by a feeling of being under siege from a common threat, secularism, first of the European colonial variety and then Arab nationalist.
A remarkable example of Sunni–Shia cooperation was the Khilafat Movement which swept South Asia following the defeat of the Ottoman Empire, the seat of the Caliphate, in World War I. Shia scholars "came to the caliphate's defence" by attending the 1931 Caliphate Conference in Jerusalem. This was despite the fact they were theologically opposed to the idea that non-Imams could be Caliphs or successors to Muhammad, and that the Caliphate was "the flagship institution" of Sunni, not Shia, authority. This has been described as unity of traditionalists in the face of the twin threats of "secularism and colonialism."
Another example of unity was a fatwā issued by the rector of Al-Azhar University, Mahmud Shaltut, recognizing Shia Islamic law as the fifth school of Islamic law. In 1959, al-Azhar University in Cairo, the most influential center of Sunni learning, authorized the teaching of courses of Shia jurisprudence as part of its curriculum.
Following this period, Sunni–Shia strife has seen a major upturn, particularly in Iraq, Afghanistan and Pakistan. Many explain the bloodshed as the work of conspiracies by outsiders—"the forces of hegemony and Zionism which aim to weaken [Islam]" (Akbar Hashemi Rafsanjani and Yusuf al-Qaradawi), unspecified "enemies" (Iran president Mahmoud Ahmadinejad), or American neo-liberals who wish to provoke "a debilitating Islamic civil war." (Dilip Hiro).
Others lay the blame for the strife at a very different source, the unintended effects of the Islamic revival. According to scholar Vali Nasr, as the Muslim world was decolonialised and Arab nationalism lost its appeal, fundamentalism blossomed and reasserted the differences and conflicts between the two movements, particularly in the strict teachings of Sunni scholar Ibn Taymiyyah. The Iranian Islamic revolution changed the Shia–Sunni power equation in Muslim countries "from Lebanon to India" arousing the traditionally subservient Shia to the alarm of traditionally dominant and very non-revolutionary Sunni. "Where Iranian revolutionaries saw Islamic revolutionary stirrings, Sunnis saw mostly Shia mischief and a threat to Sunni predominance."
Although the Iranian revolution's leader, Ayatollah Khomeini, was very much in favor of Shia–Sunni unity, he also challenged Saudi Arabia, in his view an "unpopular and corrupt dictatorship" and an "American lackey" ripe for revolution. In part because Saudi Arabia was the world's major international funder of Islamic schools, scholarships, fellowships, etc., this angered not only Saudi Arabia but its many fundamentalist allies and benefactors throughout the Sunni world.
Olivier Roy, research director at the French National Centre for Scientific Research, sees the "Shia awakening and its instrumentalisation by Iran" as leading to a "very violent Sunni reaction", starting first in Pakistan before spreading to "the rest of the Muslim world, without necessarily being as violent." According to Roy, "two events created a sea change in the balance of power between Shia and Sunnis: the Islamic revolution in Iran and the American military intervention in Iraq" in 2003. "Today, Azerbaijan is probably the only country where there are still mixed mosques and Shia and Sunnis pray together."
Shia–Sunni discord in Iraq starts with disagreement over the relative population of the two groups. According to most sources, including the CIA's World Factbook, the majority of Iraqis are Shia Arab Muslims (around 65%), and Sunnis represent about 32% of the population. However, Sunni are split ethnically between Arabs, Kurds and Turkmen. Many Sunnis hotly dispute their minority status, including ex-Iraqi Ambassador Faruq Ziada, and many believe Shia majority is "a myth spread by America". One Sunni belief shared by Jordan's King Abdullah as well as his then Defense Minister Shaalan is that Shia numbers in Iraq were inflated by Iranian Shias crossing the border. Shia scholar Vali Nasr believes the election turnout in summer and December 2005 confirmed a strong Shia majority in Iraq.
The governing regimes of Iraq were made mainly of Sunnis for nearly a century until the 2003 Iraq War. The British, having put down a Shia rebellion against their rule in the 1920s, "confirmed their reliance on a corps of Sunni ex-officers of the collapsed Ottoman empire". The British colonial rule ended after the Sunni and Shia united against it.
The Shia suffered indirect and direct persecution under post-colonial Iraqi governments since 1932, erupting into full scale rebellions in 1935 and 1936. Shias were also persecuted during the Ba'ath Party rule, especially under Saddam Hussein. Under Saddam public Shia festivals such as Ashura were banned. It is said that every Shia clerical family of note in Iraq had tales of torture and murder to recount. In 1969 the son of Iraq's highest Shia Ayatollah Muhsin al-Hakim was arrested and allegedly tortured. From 1979-1983 Saddam's regime executed 48 major Shia clerics in Iraq. They included Shia leader Mohammad Baqir al-Sadr and his sister. Tens of thousands of Iranians and Arabs of Iranian origin were expelled in 1979 and 1980 and a further 75,000 in 1989.
The Shias openly revolted against Saddam, following Gulf War in 1991, and encouraged by Saddam's defeat in Kuwait and simultaneous Kurdish uprising in the north. However, Shia opposition to the government was brutally suppressed, resulting in some 50,000 to 100,000 casualties and successive repression by Saddam's forces.
Iraq War 
Some of the worst Shia–Sunni sectarian strife ever has occurred after the start of the Iraq War, steadily building up to present. Deaths from American and allied military collateral damage have become overshadowed by the cycle of Sunni–Shia revenge killing—Sunni often using car bombs,with Shia favoring death squads.
According to one estimate, as of early 2008, 1,121 Muslim suicide bombers have blown themselves up in Iraq. Sunni suicide bombers have targeted not only thousands of civilians, but mosques, shrines, wedding and funeral processions, markets, hospitals, offices, and streets. Sunni insurgent organizations include Ansar al-Islam. Radical groups include Al-Tawhid Wal-Jihad, Jeish al-Taiifa al-Mansoura, Jeish Muhammad, and Black Banner Organization.
Takfir motivation for many of these killings may come from Sunni insurgent leader Abu Musab al-Zarqawi. Before his death Zarqawi was one to quote Muhammad ibn Abd al-Wahhab, especially his infamous statement urging followers to kill the Shia of Iraq, and calling the Shias "snakes". An al-Qaeda-affiliated website posted a call for "a full-scale war on Shiites all over Iraq, whenever and wherever they are found." Wahhabi suicide bombers continue to attack Iraqi Shia civilians, and the Shia ulama have in response declared suicide bombing as haraam:
حتي كساني كه با انتحار ميآيند و ميزنند عدهاي را ميكشند، آن هم به عنوان عمليات انتحاري، اينها در قعر جهنم هستند
Even those who kill people with suicide bombing, these shall meet the flames of hell.
Some believe the war has strengthened the takfir thinking and may spread Sunni–Shia strife elsewhere.
On the Shia side, in early February 2006 militia-dominated government death squads were reportedly "tortur[ing] to death or summarily" executing "hundreds" of Sunnis "every month in Baghdad alone," many arrested at random. According to the British television Channel 4, from 2005 through early 2006, commandos of the Ministry of the Interior which is controlled by the Badr Organization, and
...who are almost exclusively Shia Muslims — have been implicated in rounding up and killing thousands of ordinary Sunni civilians.
The violence shows little sign of getting opposite sides to back down. Iran's Shia leaders, some of whom have strong ties with Iraqi Shia, are said to become "more determined" the more violent the anti-Shia attacks in Iraq become. One Shia Grand Ayatollah, Yousef Saanei, who has been described as a moderate, reacted to the 2005 suicide bombings of Shia targets in Iraq by saying the bombers were "wolves without pity" and that "sooner rather than later, Iran will have to put them down".
Although the country of Jordan is 95% Sunni and has seen little Shia–Sunni fighting within, it has played a part in the recent Shia-Sunni strife. It is the home country of anti-Shia insurgent Raed Mansour al-Banna, who died perpetrating one of Iraq's worst suicide bombings in the city of Al-Hillah. Al-Banna killed 125 Shia and wounded another 150 in the 2005 Al Hillah bombing of a police recruiting station and adjacent open air market. In March 2005 Salt, al-Banna's home town, saw a three-day wake for al-Banna who Jordanian newspapers and celebrants proclaimed a martyr to Islam, which by definition made the Shia victims "infidels whose murder was justified." Following the wake Shia mobs in Iraq attacked the Jordanian embassy on March 20, 2005. Ambassadors were withdrawn from both countries.
All this resulted despite the strong filial bonds, ties of commerce, and traditional friendship between the two neighboring countries. Jordan, for example, had refused to ally itself against Iraq during the first Gulf War despite its alliance with America and the economic hardship that resulted.
Pakistan's citizens have had serious Shia-Sunni discord. Almost 80% of Pakistan's population is Sunni, with 20% being Shia, but this Shia minority forms the second largest Shia population of any country, larger than the Shia majority in Iraq.
Until recently Shia–Sunni relations have been cordial, and majority of people of both sects participated in the creation the state of Pakistan in 1940s. Despite the fact that Pakistan is a Sunni majority country, Shias have been elected to top offices and played an important part in the country's politics. Several top Pakistani Generals such as General Muhammad Musa. Pakistan's President Yahya Khan were Shia. President Asif Ali Zardari is a Shia. There are many intermarriages between Shia and Sunnis.
Unfortunately, from 1987–2007, "as many as 4,000 people are estimated to have died in sectarian fighting in Pakistan", 300 being killed in 2006. Amongst the culprits blamed for the killing are Al-Qaeda working "with local sectarian groups" to kill what they perceive as Shia apostates, and "foreign powers ... trying to sow discord." Most violence takes place in the largest province of Punjab and the country's commercial and financial capital, Karachi. There have also been conflagrations in the provinces of Khyber Pakhtunkhwa, Balochistan and Azad Kashmir.
Arab states especially Saudi Arabia and GCC states have been funding extremist Deobandi Sunnis and Wahabis in Pakistan, since the Afghan Jihad. Whereas Iran has been funding Shia militant groups such as Sipah-e-Muhammad Pakistan, resulting in a tit for tat attacks on each other. Pakistan has became a battleground between Saudi Arabia funded Deobandi Sunni and Wahabis and Iran funded Shia causing deaths of thousands of innocent Muslims.
Some see a precursor of Pakistani Shia–Sunni strife in the April 1979 execution of deposed President Zulfikar Ali Bhutto on questionable charges by Islamic fundamentalist General Muhammad Zia-ul-Haq. Ali Bhutto was Shia, Zia ul-Haq a Sunni.
Zia-ul-Haq's Islamization that followed was resisted by Shia who saw it as "Sunnification" as the laws and regulations were based on Sunni fiqh. In July 1980, 25,000 Shia protested the Islamization laws in the capital Islamabad. Further exacerbating the situation was the dislike between Shia leader Imam Khomeini and General Zia ul-Haq.
Shia formed student associations and a Shia party, Sunni began to form sectarian militias recruited from Deobandi and Ahl al-Hadith madrasahs. Preaching against the Shia in Pakistan was radical cleric Israr Ahmed. Muhammad Manzour Numani, a senior Indian cleric with close ties to Saudi Arabia published a book entitled Iranian Revolution: Imam Khomeini and Shiism. The book, which "became the gospel of Deobandi militants" in the 1980s, attacked Khomeini and argued the excesses of the Islamic revolution were proof that Shiism was not the doctrine of misguided brothers, but beyond the Islamic pale.
Anti-Shia groups in Pakistan include the Lashkar-e-Jhangvi and Sipah-e-Sahaba Pakistan, offshoots of the Jamiat Ulema-e-Islam (JUI). The groups demand the expulsion of all Shias from Pakistan and have killed hundreds of Pakistani Shias between 1996 and 1999. As in Iraq they "targeted Shia in their holy places and mosques, especially during times of communal prayer."  From January to May 1997, Sunni terror groups assassinated 75 Shia community leaders "in a systematic attempt to remove Shias from positions of authority." Lashkar-e-Jhangvi has declared Shia to be "American agents" and the "near enemy" in global jihad.
An example of an early Shia–Sunni fitna shootout occurred in Kurram, one of the tribal agencies of the Northwest Pakistan, where the Pushtun population was split between Sunnis and Shia. In September 1996 more than 200 people were killed when a gun battle between teenage Shia and Sunni escalated into a communal war that lasted five days. Woman and children were kidnapped and gunmen even executed out-of-towners who were staying at a local hotel.
Shia–Sunni strife in Pakistan is strongly intertwined with that in Afghanistan. Though now deposed, the anti-Shia Afghan Taliban regime helped anti-Shia Pakistani groups and vice versa. Lashkar-e-Jhangvi and Sipah-e-Sahaba Pakistan, have sent thousands of volunteers to fight with the Taliban regime and "in return the Taliban gave sanctuary to their leaders in the Afghan capital of Kabul." 
"Over 80,000 Pakistani Islamic militants have trained and fought with Taliban since 1994. They form a hardcore of Islamic activists, ever ready to carry out a similar Taliban-style Islamic revolution in Pakistan.", according to Pakistani journalist Ahmed Rashid.
Shia–Sunni strife inside of Afghanistan has mainly been a function of the puritanical Sunni Taliban's clashes with Shia Afghans, primarily the Hazara ethnic group.
In 1998 more than 8,000 noncombatants were killed when the Taliban attacked Mazar-i-Sharif and Bamiyan where many Hazaras live. Some of the slaughter was indiscriminate, but many were Shia targeted by the Taliban. Taliban commander and governor Mullah Niazi banned prayer at Shia mosques and expressed takfir of the Shia in a declaration from Mazar's central mosque:
Last year you rebelled against us and killed us. From all your homes you shot at us. Now we are here to deal with you. The Hazaras are not Muslims and now have to kill Hazaras. You either accept to be Muslims or leave Afghanistan. Wherever you go we will catch you. If you go up we will pull you down by your feet; if you hide below, we will pull you up by your hair.
Assisting the Taliban in the murder of Iranian diplomatic and intelligence officials at the Iranian Consulate in Mazar were "several Pakistani militants of the anti-Shia, Sipah-e-Sahaba party."
Iran and Shia statehood 
Iran is unique in the Muslim world because its population is overwhelmingly more Shia than Sunni (Shia constitute 92% of the population) and because its constitution is theocratic republic based on rule by a Shia jurist.
Although the founder of the Islamic Republic, Ayatollah Ruhollah Khomeini, supported good Sunni–Shia relations, there have been complaints by Sunni of discrimination, particularly in important government positions. In a joint appearance with former Iranian president Akbar Hashemi Rafsanjani calling for Shia-Suni unity, Sunni Shiekh Yusuf al-Qaradawi complained that no ministers in Iran have been Sunni for a long time, that Sunni officials are scarce even in the regions with majority of Sunni population (such as Kurdistan, or Balochistan). Sunnis cite the lack of a Sunni mosque in Tehran, Iran's capital and largest city, despite the presence of over 1 million Sunnis there, and despite the presence of Christian churches, as a prominent example of this discrimination. Although reformist President Mohammad Khatami promised during his election campaign to build a Sunni mosque in Tehran, none was built during his eight years in office. The president explained the situation by saying Supreme Leader Ayatollah Ali Khamenei would not agree to the proposal. As in other parts of the Muslim world, other issues may play a part in the conflict, since most Sunnis in Iran are also ethnic minorities.
Soon after the 1979 revolution Sunni leaders from Kurdistan, Balouchistan, and Khorassan, set up a new party known as Shams, which is short for Shora-ye Markaz-e al Sunaat, to unite Sunnis and lobby for their rights. But six months after that, they were closed down, bank accounts suspended, and had their leaders arrested by the government on charges that they were backed by Saudi Arabia and Pakistan.
...information indicates Sunnis, along with other religious minorities, are denied by law or practice access to such government positions as cabinet minister, ambassador, provincial governor, mayor and the like, Sunni schools and mosques have been destroyed, and Sunni leaders have been imprisoned, executed and assassinated. The report notes that while some of the information received may be difficult to corroborate there is a clear impression that the right of freedom of religion is not being respected with regard to the Sunni minority.
Members of the 'Balochistan Peoples Front' claim that Sunnis are systematically discriminated against educationally by denial of places at universities, politically by not allowing Sunnis to be army generals, ambassadors, ministers, prime minister, or president, religiously insulting Sunnis the media, economic discrimination by not giving import or export licenses for Sunni businesses while the majority of Sunnis are left unemployed.
There has been a low level resistance in mainly Sunni Iranian Balouchistan against the regime for several years. Official media refers to the fighting as armed clashes between the police and "bandits," "drug-smugglers," and "thugs," to disguise what many believe is essentially a political-religious conflict. Revolutionary Guards have stationed several brigades in Balouchi cities, and have allegedly tracked down and assassinated Sunni leaders both inside Iran and in neighboring Pakistan. In 1996 a leading Sunni, Abdulmalek Mollahzadeh, was gunned down by hitmen allegedly hired by Tehran as he was leaving his house in Karachi.
Members of Sunni groups in Iran however have been active in what the authorities describe as terrorist activities. Balochi Sunni Abdolmalek Rigi continue to declare the Shia as Kafir and Mushrik. These Sunni groups have been involved in violent activities in Iran, and have waged terrorist attacks against civilian centers, including an attack next to a girl's school according to government sources. The "shadowy Sunni militant group Jundallah" has reportedly been receiving weaponry from the United States for these attacks according to the semi-official Fars News Agency. The United Nations and several countries worldwide have condemned the bombings. (See 2007 Zahedan bombings for more information)
Non-Sunni Iranian opposition parties, and Shia like Ayatollah Jalal Gange’i have criticised the regimes treatment of Sunnis and confirmed many Sunni complaints.
Following the 2005 elections, much of the leadership of Iran has been described as more "staunchly committed to core Shia values" and lacking Ayatollah Khomeini's commitment to Shia–Sunni unity. Polemics critical of Sunnis were reportedly being produced in Arabic for dissemination in the Arab Muslim world by Hojjatieh-aligned elements in the Iranian regime.
Syria is approximately three quarters Sunni, but its government is predominately Alawi, a Shia sect that makes up less than 15% of the population. Under Hafez al-Assad, Alawi dominated the Baath Arab Socialist Party, a secular Arab nationalist party which has ruled Syria under a state of emergency since 1963 and has not tolerated any opposition. Alawi are often considered a form of Shia Islam, that differs somewhat from the larger Twelver Shia sect.
A very serious 20th century conflict in Syria with sectarian religious overtones was that between the Alawi-dominated al-Assad regime and the Islamist Sunni Muslim Brotherhood, culminating with the 1982 Hama massacre. An estimated 10,000 to 40,000 Syrians, mostly civilians, were killed by Syrian military and the American back terrorists. During the uprising, the Sunni Muslim Brotherhood attacked military cadets at an artillery school in Aleppo, performed car bomb attacks in Damascus, as well as bomb attacks against the government and its officials, including Hafez al-Assad himself, and had killed several hundred.
How much of the conflict was sparked by Sunni versus Shia divisions and how much by Islamism versus secular-Arab-nationalism, is in question, but according to scholar Vali Nasr the failure of the Ayatollah Khomeini and the Islamic Republic of Iran to support the Muslim Brotherhood against the Baathists "earned [Khomeini] the Brotherhood's lasting contempt." It proved to the satisfaction of the Brotherhood that sectarian loyalty trumped Islamist solidarity for Khomeini and eliminated whatever appeal Khomeini might have had to the MB movement as a pan-Islamic leader.
The 2011-2012 Syrian uprising has reawakened the sectarian tensions in Syria, gradually becoming a full-blown sectarian strife between the Alawi dominated Army and government vs. Sunni rebels and former members of the regular Syrian Army.
Though sectarian tensions in Lebanon were at their height during the Lebanese Civil War, the Shia–Sunni relations were not the main conflict of the war. The Shia parties of Hizbullah emerged in Lebanon during the Lebanese Civil War, and emerged as one of the strongest forces following the Israeli withdrawal in the year 2000, and the collapse of the SLA in the South. The situation in Lebanon flared into anti-Shia moods with the assassination of Sunni Rafiq al-Hariri, with Hizbullah and Syria being the main suspects. The tensions blew into a limited warfare between Shia dominated vs Sunni dominated political alliances in 2008. The Shia organization has since attempted to lower the profile. With the eruption of the 2011-2012 Syrian uprising, tensions increased between the Shia affiliated Alawis and Sunnis of Tripoli, erupting twice into deadly violence - on June 2011, and the second time on February 2012.
Muslims in Yemen including Shafi'i (Sunni) majority and Zaydi (Shia) minority. Zaidi are sometimes called "Fiver Shia" instead of Twelver Shia because they recognize the first four of the Twelve Imams but accept Zayd ibn Ali as their "Fifth Imām" rather than his brother Muhammad al-Baqir. Shia–Sunni conflict in Yemen involves the Sa'dah insurgency.
Both Shia and Sunni dissidents in Yemen have similar complaints about the government—cooperation with the American government and an alleged failure to following Sharia law—but it's the Shia who have allegedly been singled out for government crackdown.
During and after the US-led invasion of Iraq, members of the Zaidi-Shia community protested after Friday prayers every week outside mosques, particularly the Grand Mosque in Sana'a, during which they shouted anti-US and anti-Israeli slogans, and criticised the government's close ties to America. These protests were led by ex-parliament member and Imam, Bader Eddine al-Houthi. In response the Yemeni government has implemented a campaign to crush "the Zaidi-Shia rebellion," and harass journalists.
The small Persian Gulf island state of Bahrain has a Shia majority but is ruled by Sunni Al Khalifa family as a constitutional monarchy, with Sunni dominating the ruling class and military and disproportionately represented in the business and landownership. According to the CIA World Factbook, Al Wefaq the largest Shia political society, won the largest number of seats in the elected chamber of the legislature. However, Shia discontent has resurfaced in recent years with street demonstrations and occasional low-level violence."
Bahrain has many disaffected unemployed Shia youths and many Shia have protested Sheikh Hamad bin Isa Al Khalifa's efforts to create a parliament as merely a "cooptation of the effendis", i.e. traditional elders and notables. Bahrain's 2002 election was widely boycotted by Shia. Mass demonstrations by Shia have been held in favor of full fledged democracy in March and June 2005, against an alleged insult to Ayatollah Khamenei in July 2005.
An example of governments working "to drive wedges between Sunnism and Shiism" was found in Nigeria in 1998 when the Nigerian government of General Sani Abacha accused Muslim Brotherhood leader Sheikh Ibrahim al-Zak Zaki of being a Shia. This was despite the fact that there are few if any Shia among Nigerias Muslims and the Muslim Brotherhood is a Sunni organization.
Saudi Arabia 
While Shia make up roughly 15% of Saudi Arabia's population, they form a large portion of the residents of the eastern province of Hasa—by some estimates a majority—where much of the petroleum industry is based. Between 500,000 and a million Shia live there, concentrated especially around the oases of Qatif and Al-Hasa. The Majority of Saudi Shia belong to the sect of the Twelvers.
Relations between the Shia and the Wahhabis are inherently strained because the Wahhabis consider the rituals of the Shia to be the epitome of shirk, or polytheism. In the late 1920s, the Ikhwan (Ibn Saud's fighting force of converted Wahhabi Bedouin Muslims) were particularly hostile to the Shia and demanded that Abd al Aziz forcibly convert them. In response, Abd al Aziz sent Wahhabi missionaries to the Eastern Province, but he did not carry through with attempts at forced conversion. In recent decades the late leading Saudi cleric, Abd al-Aziz ibn Abd Allah ibn Baaz, issued fatwa denouncing Shia as apostates, and according to Shia scholar Vali Nasr "Abdul-Rahman al-Jibrin, a member of the Higher Council of Ulama, even sanctioned the killing of Shias, a call that was reiterated by Wahhabi religious literature as late as 2002."
Government policy has been to allow Shia their own mosques and to exempt Shia from Hanbali inheritance practices. Nevertheless, Shia have been forbidden all but the most modest displays on their principal festivals, which are often occasions of sectarian strife in the Persian Gulf region, with its mixed Sunni–Shia populations.
According to a report by the Human Rights Watch:
Shia Muslims, who constitute about eight percent of the Saudi population, faced discrimination in employment as well as limitations on religious practices. Shia jurisprudence books were banned, the traditional annual Shia mourning procession of Ashura was discouraged, and operating independent Islamic religious establishments remained illegal. At least seven Shi'a religious leaders-Abd al-Latif Muhammad Ali, Habib al-Hamid, Abd al-Latif al-Samin, Abdallah Ramadan, Sa'id al-Bahaar, Muhammad Abd al-Khidair, and Habib Hamdah Sayid Hashim al-Sadah-reportedly remained in prison for violating these restrictions."
And Amnesty International adds:
Members of the Shi‘a Muslim community (estimated at between 7 and 10 per cent of Saudi Arabia’s population of about 19 million) suffer systematic political, social, cultural as well as religious discrimination.
As of 2006 four of the 150 members of Saudi Arabia's "handpicked" parliament were Shia, but no city had a Shia mayor or police chief, and none of the 300 girls schools for Shia in the Eastern Province had a Shia principal. According to scholar Vali Nasr, Saudi textbooks "characterize Shiism as a form of heresy ... worse than Christianity and Judaism."
Forced into exile in the 1970s, Saudi Shia leader Hassan al-Saffar is said to have been "powerfully influenced" by the works of Sunni Islamists of the Muslim Brotherhood and Jamaat-e-Islami and by their call for Islamic revolution and an Islamic state.
Following the 1979 Iranian Revolution, Shia in Hasa ignored the ban on mourning ceremonies commemorating Ashura. When police broke them up three days of rampage ensued—burned cars, attacked banks, looted shops—centered around Qatif. At least 17 Shia were killed. In February 1980 disturbances were "less spontaneous" and even bloodier. Meanwhile broadcasts from Iran in the name of the Islamic Revolutionary Organization attacked the monarchy, telling listeners, "Kings despoil a country when they enter it and make the noblest of its people its meanest ... This is the nature of monarchy, which is rejected by Islam."
By 1993, Saudi Shia had abandoned uncompromising demands and some of al-Saffar's followers met with King Fahd with promised made for reform. In 2005 the new King Abdullah also relaxed some restrictions on the Shia. However Shia continue to be arrested for commemorating Ashura as of 2006. In December 2006, amidst escalating tensions in Iraq, 38 high ranking Saudi clerics called on Sunni Muslims around the world to "mobilise against Shiites".
Shia Grand Ayatollah Naser Makarem Shirazi is reported to have responded:
Saudi Sunni 
A large fraction of the foreign Sunni extremists who have entered Iraq to fight against Shia and the American occupation are thought to be Saudis. According to one estimate, of the approximately 1,200 foreign fighters captured in Syria between summer 2003 and summer 2005, 85% were Saudis.
Another reflection of grassroots Wahhabi or Saudi antipathy to Shia was statement by Saudi cleric Nasir al-Umar, who accused Iraqi Shias of close ties to the United States and argued that both were enemies of Muslims everywhere.
Some Wahabi groups, often labeled as takfiri and sometimes linked to Al-Qaeda, have even advocated the persecution of the Shia as heretics. Such groups have been allegedly responsible for violent attacks and suicide bombings at Shi'a gatherings at mosques and shrines, most notably in Iraq during the Ashura mourning ceremonies where hundreds of Shias were killed in coordinated suicide bombings, but also in Pakistan and Afghanistan. However Al-Qaeda deputy Dr Ayman al-Zawahiri in a video message directed Abu Musab al-Zarqawi, of Al-Qaeda in Iraq, not to attack civilian targets but to focus on the occupation troops. His call seems to have been ignored, or swept away in the increasing tensions of Iraq under occupation.
United States 
In late 2006 or early 2007, in what journalist Seymour Hersh called The Redirection, the United States changed its policy in the Muslim world, shifting its support from the Shia to the Sunni, with the goal of "containing" Iran and as a by-product bolstering Sunni extremist groups. Richard Engel, who is an NBC News Chief Foreign Correspondent, wrote an article in late 2011 alleging that the United States Government is pro-Sunni and anti-Shia. During the Iraq War, the United States feared that a Shiite-led, Iran-friendly Iraq could have major consequences for American national security. However, nothing can be done about this as Iraq's Shiite government were democratically elected. Shadi Bushra of Stanford University wrote that the United States’ support of the Sunni monarchy during the Bahraini uprising is the latest in a long history of US support to keep the Shiites in check. The United States fears that Shiite rule in the Gulf will lead to anti-US and anti-Western sentiment as well as Iranian influence in the Arab majority states.
One analyst told CNN that the US strategy on putting pressure on Iran by arming its Sunni neighbors is not a new strategy for the United States. "Remember what President Bush tried to do was kind of create a Sunni axis against the Shi’a Iran, by arming our Sunni allies, our so-called moderate Sunni allies...I’m not exactly sure if that’s the best idea going forward, because as you know, this is not the Middle East that we were dealing with during the Bush administration. We no longer have just a handful of dictators that we can tell what to do."
Efforts to foster Sunni–Shia unity 
In a special interview broadcast on Al Jazeera on February 14, 2007, former Iranian president and chairman of the Expediency Discernment Council of Iran, Ayatollah Akbar Hashemi Rafsanjani and highly influential Sunni scholar Yusuf Al-Qaradawi, "stressed the impermissibility of the fighting between the Sunnis and the Shi’is" and the need to "be aware of the conspiracies of the forces of hegemony and Zionism which aim to weaken [Islam] and tear it apart in Iraq." 
Even on this occasion there were differences, with Rafsanjani openly asking "more than once who started" the inter-Muslim killing in Iraq, and Al-Qaradawi denying claims by Rafsanjani that he knew where "those arriving to Iraq to blow Shi’i shrines up are coming from".
International Islamic Unity Conference 
Saudi-Iran summit 
In a milestone for the two countries' relations, on March 3, 2007 King Abdullah of Saudi Arabia and President Mahmoud Ahmadinejad held an extraordinary summit meeting. They displayed mutual warmth with hugs and smiles for cameras and promised "a thaw in relations between the two regional powers but stopped short of agreeing on any concrete plans to tackle the escalating sectarian and political crises throughout the Middle East."
On his return to Tehran, Ahmadinejad declared that:
Both Iran and Saudi Arabia are aware of the enemies' conspiracies. We decided to take measures to confront such plots. Hopefully, this will strengthen Muslim countries against oppressive pressure by the imperialist front.
Saudi officials had no comment about Ahmadinejad's statements, but the Saudi official government news agency did say:
The two leaders affirmed that the greatest danger presently threatening the Islamic nation is the attempt to fuel the fire of strife between Sunni and Shiite Muslims, and that efforts must concentrate on countering these attempts and closing ranks,
Saudi Foreign Minister Prince Saud bin Faisal bin Abdul-Aziz said:
The two parties have agreed to stop any attempt aimed at spreading sectarian strife in the region.
See also 
- Amman Message
- Criticism of Twelver Shi'ism
- Modern usage of al-Qādisiyyah
- Shi'a Muslims in the Arab world
- "Religions". CIA. The World Factbook. 2010. Retrieved 2010-08-25.
- "Sunnite". Encyclopædia Britannica Online. 2010. Retrieved 2010-08-26.
- "Islām". Encyclopædia Britannica Online. 2010. Retrieved 2010-08-26.
- "Mapping the Global Muslim Population: A Report on the Size and Distribution of the World’s Muslim Population". Pew Research Center. October 7, 2009. Retrieved 2010-08-26.
- Miller, Tracy, ed. (10 2009). Mapping the Global Muslim Population: A Report on the Size and Distribution of the World’s Muslim Population (PDF). Pew Research Center. Retrieved 2009-10-08.
- "Shīʿite". Encyclopædia Britannica Online. 2010. Retrieved 2010-08-25.
- Glasse, Cyril, The New Encyclopedia of Islam
- Esposito, John L., The Oxford Dictionary of Islam
- The fundamentalist dimension in the Pakistan Movement :
- CRS Report for Congress, Islam: Sunnis and Shiites
- Nasr, Vali, The Shia Revival, Norton, 2006, p.106
- Civil War
- Mapping the Global Muslim Population
- World Religions
- Administrative Department of the President of the Republic of Azerbaijan - Presidential Library - Religion
- "Background Note: Tajikistan". State.gov. Retrieved 2009-10-02.
- "The Shia Revival: How Conflicts within Islam Will Shape the Future". Vali Nasr, Joanne J. Myers. October 18, 2006. Retrieved 2010-08-24.
- "The Revival of Shia Islam (Archived)". Vali Nasr. Washington, D.C.: The Pew Forum on religion & public life. July 24, 2006. Archived from the original on 2008-03-06. Retrieved 2010-08-27. "The Shiites—just as an introduction—are about 20 to 35 percent of the Muslim population worldwide, which makes them about 230 million to 390 million people."
- Nasr, Vali, The Shia Revival, Norton, 2006, p.38
- Glasse, Cyril, The New Encyclopedia of Islam, Altamira Press, 2001, p.280
- Martin, Richard C., ed. (2004), "Mahdi", Encyclopedia of Islam and the Muslim world, Thompson Gale, p. 421
- Nasr, Vali, The Shia Revival, Norton, 2006, p.68
- Nasr, Vali, The Shia Revival, Norton, 2006, p.59-60
- "The Origins of the Sunni/Shia split in Islam". IslamForToday.com. Retrieved 2007-01-29.
- Nasr, Vali, The Shia Revival, Norton, 2006, p.43
- "Misyar marriage". lexicorient.com. Retrieved 2009-08-25.
- Ya'qubi; vol.lll, pp.91-96, and Tarikh Abul Fida' , vol. I, p.212.
- Bihar al-Anwar, vol. XII, on the life of Imam Ja'far al-Sadiq
- Shi'a Islam, p62
- Ya'qubi. vol.ll, p.224; Abu'l-Fida', vol.l, p.192; Al-Masudi, vol.lll, p.81', also Shi'a Islam, p60.
- Nasr, Vali, The Shia Revival, Norton, 2006, p.108
- Nasr, Vali, The Shia Revival, Norton, 2006, p.110
- Islam and Iran: A Historical Study of Mutual Services
- Four Centuries of Influence of Iraqi Shiism on Pre-Safavid Iran
- Article by Sayyid 'Ali ibn 'Ali al-Zaidi, A short History of the Yemenite Shi‘ites (2005) Referencing: Iranian Influence on Moslem Literature
- Article by Sayyid 'Ali ibn 'Ali Al-Zaidi, A short History of the Yemenite Shi‘ites (2005) Referencing: Encyclopedia Iranica
- A Study of the Migration of Shi'i Works from Arab Regions to Iran at the Early Safavid Era
- al-Ka-mil of Ibn Athir, Cairo, 1348; Raudat al-safa' ; and Habib as-Siyar of Khwand Mir
- Abu'l-Fida' , vol.ll, p.63 and vol.lll, p.50
- Hossein Nasr (1972) p.115
- Nasr (1972) p.116
- Shah Ismail I, 1501-26
- Frequently Asked Questions on Iran
- An introduction to Shi'i Islam: the history and doctrines of Twelver Shi'ism By Moojan Momen, #121.
- Muhammad Hussain Najafi, Ahsan ul-Fawaid pp. 38
- "Shias of Kashmir – Socio Political Dilemmas". Kashmir Observer. Retrieved 2010-07-01.
- Momen, Moojan, An Introduction to Shi'i Islam, Yale University Press, 1985, p.276
- Momen, Moojan, An Introduction to Shi'i Islam, Yale University Press, 1985, p.277
- Wright, Robin, Sacred Rage, Simon and Schuster, (2001), p.149-158
- Information on sectarian violence against Sunni Muslims UNHCR
- Nasr, Vali, The Shia Revival, Norton, 2006, p.107
- Rafsanjani & Al-Qaradawi call upon nation to unite & reject fighting
- "Saudi king meets with Iranian president". International Herald Tribune by Hassan M. Fattah, March 4, 2007
- The enemy of my enemy March 6, 2007 Dilip Hiro
- Nasr, Vali, The Shia Revival, Norton, 2006, p.106-7
- Nasr, Vali, The Shia Revival, Norton, (2006), p.148-50
- Nasr, Vali, The Shia Revival, Norton, (2006), p.143-4
- Nasr, Vali, The Shia Revival, Norton, (2006), p.143-4, 147-8, 150-1
- Roy, Olivier, The Politics of Chaos in the Middle East, Columbia University Press, 2008 (p.105)
- CIA World Factbook. Iraq
- "Iraqis By the Numbers" by FARUQ ZIADA
- Nasr, Vali, The Shia Revival, Norton, (2006), p.200
- Robin Wright and Peter Baker, "Iraq: Jordan Sees Threat to the Election from Iran", Washington Post, Dec. 8, 2004
- Nasr, Vali, The Shia Revival, Norton, (2006), p.201
- The Arab Shia, p46
- Nasr, Vali, The Shia Revival, (Norton, 2006), p.187
- according to pro-Khomeini author Abdel-Majid Trab Zemzem, in his book The Iraq-Iran War, Islam and Nationalisms, translated from the French by Zinab Mohammad, , United States Publishing Company, 1986, p.42-3
- Nasr, Vali, The Shia Revival, Norton, (2006), p.110
- The media are minimising US and British war crimes in Iraq, George Monbiot in The Guardian, Tuesday November 8, 2005
- The Rise of Shia Death Squads[dead link]
- March 14, 2008 The Independent/UK "The Cult of the Suicide Bomber" by Robert Fisk "month-long investigation by The Independent, culling four Arabic-language newspapers, official Iraqi statistics, two Beirut news agencies and Western reports"
- over half of the 20,000 fatalities worldwide from terrorism in 2006 occurred in Iraq according to the American National Counter-terrorism Center Report on Terrorist Incidents 2006 p.3
- Al Jazeera English - News - Car Bomb Blast Near Iraq Shrine
- Iraqi funeral procession bombed; at least 26 killed
- Nasr, Vali, The Shia Revival, (Norton, 2006), p.203
- Ansar al-Islam is listed as a terrorist group by the US State Dept
- US Dept. of State. Chapter 5 - Country Reports: Middle East and North Africa Overview
- Al Jazeera SEPTEMBER 17, 2005, "Al-Zarqawi declares war on Iraqi Shia," Accessed Feb 20, 2008
- "Zarqawi rails against Shia 'snakes'" The Daily Telegraph, 03/06/2006, Accessed Feb 7, 2007.
- New York Times, September 19, 2005, Sabrina Tavernise and Robert F. Worth, "Relentless Rebel Attacks Test Shiite Endurance",
- CBC News: "Sectarian violence kills 36 during climax of Shia holy festival". Jan 2007.
- Ayatollah Yousef Saanei's interview with CNN, Feb 6, 2007: Ayatollah Yousef Sanei fatwa (in Persian)
- The Iraqi Effect: The War has increased terrorism worldwide sevenfold
- Iraq's death squads
- Iraq 'failing to tackle death squads'
- "Iraq militias' wave of death, Sectarian killings now surpass terrorist bombings," The Boston Globe, April 2, 2006
- Channel 4 program Dispatches
- Nasr, Vali, The Shia Revival (Norton 2006), p.223
- Robert Baer, "The Devil You Think You Know," Newsweek International, August 15, 2005. Originally on MSNBC, now on Mangan's "The Devil You Think You Know"
- Iraq-Jordan Dispute Deepens; Diplomats Recalled in Aftermath of Suicide Bombing, March 21, 2005 The Washington Post
- Nasr, Vali, The Shia Revival (Norton, 2006), p.227-8
- Nasr, Vali, The Shia Revival (Norton), 2006, p.160
- The fundamentalist dimension in the Pakistan Movement
- "Shiite-Sunni conflict rises in Pakistan," by David Montero, February 02, 2007
- "Pakistan's Shia-Sunni divide". BBC News. June 1, 2004.
- Nasr, Vali, The Shia Revival, Norton, (2006), p.89
- Nasr, Vali, The Shia Revival, Norton, (2006), p.161-2
- Nasr, Vali, The Shia Revival, Norton, (2006), p.164
- Rashid, Taliban (2000), p.194
- Nasr, Vali, The Shia Revival, Norton, (2006), p.166
- Nasr, Vali, The Shia Revival, Norton, (2006), p.167
- Nasr, Vali, The Shia Revival, Norton, (2006), p.168
- Kaplan, Robert, Soldiers of God : With Islamic Warriors in Afghanistan and Pakistan, New York : Vintage Departures, 2001, p.242
- Rashid, Taliban (2000), p.263
- Goodson, Afghanistan's Endless War, (2001), p.79
- Rashid,Taliban (2000), p.73
- Human Rights Watch Report, `Afghanistan, the massacre in Mazar-e-Sharif`, November 1998. INCITEMENT OF VIOLENCE AGAINST HAZARAS BY GOVERNOR NIAZI
- Rashid,Taliban (2000), p.74
- Interview with Molavi Ali Akbar Mollahzadeh The Iran Brief,
- Al-Jazeera discussion between Qardawi and Rafsanjani Rafsanjani & Al-Qaradawi call upon nation to unite & reject fighting, 2007-02-15
- International Religious Freedom Report 2004
- Iran's unsung rebellion By Syed Saleem Shahzad
- UN Human Rights System, Report of the Special Representative on Iran
- Visit by the Special Rapporteur to the Islamic Republic of Iran
- Shia equality or Shia supremacy? Balochistan People's Front Reza Hossein Borr, leadership consultant and author of "New Vision for the Islamic World"
- Interview with Molavi Ali Akbar Mollahzadeh The Iran Brief, Issue Number 35, June 2, 1997
- Source quoting the newspaper Entekhab: varedi-st.persianblog.ir[dead link]
- Zahedan bombings intended to foment Sunni-Shia conflict: governor
- No casualties in renewed bombing in south-east Iran 02/16/07
- See Weapons used in Terrorist Attacks in southeastern Iran on ground forces of Iran's Revolutionary Guards Corps, came from the US according to the semi-official Fars News Agency , Global Research, February 18, 2007
- londonontario.indymedia.org[dead link]
- UNSC condemns terrorist act in Iran's Zahedan
- Solana condemns Zahedan, Iran terror attack, February 17, 2007Georgia condemns terrorist bombing in Zahedan Tehran, Feb 17, IRNA
- NCRI Statement, "Ahmadinejad sheds crocodile tears for Sunnis in Iran"
- Nasr, Vali, The Shia Revival, Norton, (2006), p.225
- "Shia Supremacists Emerge from Iran's Shadows" Asia Times, August 27, 2005
- World Factbook - Syria
- Dictionary.com definition
- Nasr, Vali, The Shia Revival, Norton, (2006), p.154
- Yemen Facing Insurgency on Two Fronts, By Stephen Ulph (see above)
- Amnesty Report
- Yemeni President: al-Houthi is an ill man, mentally abnormal
- Clashes 'leave 118 dead' in Yemen, BBC report
- Yemen: Harassment of journalists must stop
- Yemen Facing Insurgency on Two Fronts, By Stephen Ulph, Jamestown Foundation
- Amnesty: Yemen: The Rule of Law Sidelined in the Name of Security
- Amnesty: Ratification without implementation:the state of human rights in Yemen 
- Momen, Moojan, Introduction to Shi'i Islam, Yale University Press, 1985, p.145
- CIA World Factbook - Bahrain
- Nasr, Vali, The Shia Revival, Norton, (2006), p.234-5
- Nasr, Vali, The Shia Revival, Norton, (2006), p.156
- Saudi Arabia's Shia press for rights retrieved 19 July 2012
- "The country's minority Shia populations form a majority in the country's oil rich eastern province of Hasa" Neighbours eye Iraq elections By Sam Sasan Shoamanesh
- Nasr, Vali, The Shia Revival, Norton, (2006), p.236
- Library of Congress: Saudi Arabia
- Toby Jones, `The Iraq Effect in Saudi Arabia,` Middle East Report, 237, Winter 2005, p.24
- HRW Link: Human Rights Developments Saudi Arabia
- Amnesty report[dead link]
- Nasr, Vali, The Shia Revival, Norton, (2006), p.237
- "The Shiite Question in Saudi Arabia", Middle East Report, 45, International Crisis Group, 2005, p.3. Quoted in Nasr, Vali, The Shia Revival, Norton, (2006), p.117
- Wright, Robin, Sacred Rage, Simon and Schuster, (2001), p.150
- BBC monitoring service from March 1980 quoted in William B. Quandt, Saudi Arabia in the 1980s, Brookings Institution, 1981, pp.39-40
- Nasr, Vali, The Shia Revival, Norton, (2006), p.238, 240
- Human Rights Watch Saudi Arabia - Events of 2006
- Saudi clerics seek help for Iraqi Sunnis
- Press release by Iranian Students News Agency: www.isna.ir[dead link]
- Jones, Toby "The Iraq Effect in Saudi Arbia, Middle East Report 237 (Winter 2005), p.24
- Al-Zarqawi declares war on Iraqi Shia aljazeera.net, 14 September 2005
- Baghdad goes under curfew after bombing of a Shia shrine in Samarra
- Blasts target Iraq's Shia Muslims on the eve of Ashura 18 February 2005
- Latest Iraq blast targets Shia mosque, September 16, 2005 "Abu Musab al-Zarqawi, vowed to wage an 'all-out war' on the country's Shia majority"
- "Four days after al-Qaeda in Iraq declared all-out war on the Shiite majority, more than 250 people have been killed" San Diego Union Tribune, September 18, 2005
- Hersh, Seymour M. (March 5, 2007). "Annals of National Security: The Redirection". The New Yorker.
- Richard Engel (December 14, 2011). "Post-US Iraq: Welcome to Shia-stan". MSNBC.
- Saudi king meets with Iranian president By Hassan M. Fattah, iht.com, March 4, 2007
- Saudi king meets with Iranian president - International Herald Tribune
- Iran Supports Efforts to End Lebanon Crisis, Fight Inter-Muslim Strife
- Ahmadinejad, Saudi king reject sectarian strife
Further reading 
|Wikiquote has a collection of quotations related to: Sunni-Shia relations|
- Crescent: “The Shia Crescent”, (English)
- Nasr, Hossein (1972). Sufi Essays. Suny press. ISBN 978-0-87395-389-4.
- The Arab Shia: The Forgotten Muslims, by Graham E. Fuller and Rend Rahim Francke. New York: Saint Martin's Press, 1999, ISBN 0-312-23956-4
- Shi'a Islam, by Muhammad Husayn Tabatabaei and Hossein Nasr, SUNY Press, 1979. ISBN 978-0-87395-272-9
- Don’t Fear the Shiites: The Idea of a Teheran-Controlled »Shiite Crescent« over the Greater Middle East is at Odds with Reality, by Michael Bröning. In: International Politics and Society, 3 /2008, pp. 60–75.