|Part of Iran–Iraq War|
Mujahadeen-e-Khalq (MEK) army was destroyed in 1988
| National Liberation Army (MEK)
Peshmerga (only in the northern sector)
|Commanders and leaders|
|Massoud Rajavi||Ali Sayad Shirazi|
unknown number of artillery pieces and aircraft
unknown number of artillery pieces and aircraft
|Casualties and losses|
|4,500 KIA (Iranian claim)
2,000 KIA (independent estimate)
several thousand hanged for treason
|400 KIA (Iranian claim)|
Operation Mersad was the name given by the Iranian government, taken from the Persian word meaning 'ambush' was the last major military operation of the war, ending in a decisive victory for Iran. The operation involved a successful counterattack against a July 1988 military incursion from Iraq, by a military force of about 7000 members of the Mujahadeen-e-Khalq (MEK). The MEK soldiers were armed, equipped and given air support by Iraq and other foreign states. Led by Lt. General Ali Sayad Shirazi, Operation Mersad began on 26 July 1988 and lasted only a few days, where the Iranian Armed Forces crushed the MEK in what was the last military operation of any significance of the Iran–Iraq War.
Both Iran and Iraq had accepted United Nations Security Council Resolution 598, which would end the war on 20 July 1988. However, shortly thereafter the Iraqi supported Mujahedeen-e-Khalq militant group attacked central Iran. The attacks was decisively defeated by the Iranian military.
After almost eight years of bloody warfare, the Iran Iraq War was coming to an end under the United Nations Security Council Resolution 598, which was passed 20 July 1987. Iran had suffered several defeats in southern Iraq during the Second Battle of Al Faw and Operation Tawakalna ala Allah, and had decided to accept the UN ceasefire. However, made confident by recent Iraqi victories, Iraqi dictator Saddam Hussein decided to violate the ceasefire agreement and let the MEK launch an invasion of Iran itself.
The attack agreed upon by the Iraqi leadership would be a two pronged assault. Another group would attack forces in Iranian and Iraqi Kurdistan, the latter area still within Iranian and Peshmerga hands. When the Iranian armies moved to fight that in Kurdistan, the renegade Iranian militant group the Mujahedeen-e-Khalq (MEK), supported by Iraqi air power, would launch a large scale incursion into the central portion of Iran, aiming towards the heart of Iran. The MEK under their leader Massoud Rajavi harbored the hope that the attack would lead to a general uprising against the Islamic government of Ayatollah Khomeini. Rajavi would lead the Mujahedeen with Iraqi support in an attack on the western borders of Iran.
While Operation Mersad only specifically applies to the Iranian counterattack against the Mujahedeen attack, this article covers all of the post ceasefire attacks from Iraq as well.
MEK launches Operation Forough Javidan
On 26 July 1988, the MEK, with the support of the Iraqi military, started their campaign, Operation Forough Javidan (Eternal Light) in central Iran. The Mujahedeen worked with the Iraqi air force, advancing towards Kermanshah. With few Iranian troops in the field, the MEK advanced very rapidly, seizing and destroying the towns of Qasr-e Shirin, Sarpol-e Zahab, Kerend-e Gharb, and Islamabad-e Gharb, and pushing towards the provincial capital city of Kermanshah. The Mujahedeen expected the Iranian population to rise up and support their advance; however, the uprising never materialised. Except for an Iranian Kurdish resistance, the Mujahedeen drove through unopposed, pushing 145 km (90 mi) deep into Iran. Iran's Kurdish fighters did manage to slow the Iraqi supported Mujahedeen advance, allowing time for the Iranians to prepare their counteroffensive.
Iran did not launch an immediate attack against the Mujahedeen. Instead they waited until they were deep enough inside of Iran that Iraq's air support could no longer effectively support their advance. The MEK continued to advance, reaching as far as 145 km (90 mi) deep into Iran, and the road to Tehran seemed to be wide open.
The Iranians waited until the opposing forces reached deep enough where Iraqi air support would be unable to properly support the advance. Afterwards, Iranian paratroopers landed behind the MEK lines while the Iranian Air Force F-4 Phantoms bombed the Mujahedeen vehicles on the Kermanshah highway. Afterwards, helicopters launched an air attack using anti-tank missiles. By this time, most of the enemy armour was destroyed, in a miniature version of the Highway of Death during the Gulf War. The MEK advance had been abruptly and completely halted.
The Iranian army and Revolutionary Guard then moved north from Khuzestan, encircling and suppressing the remaining resistance in the city of Kerend-e Gharb on 29 July 1988.
On 31 July, Iran drove MEK forces out of Qasr-e-Shirin and Sarpol Zahab, though MEK claimed to have "voluntarily withdrawn" from the towns. Iran estimated that 1,500 Mujahedeen soldiers were killed, while 4000 Iranian soldiers died. The Iranian successes during Operation Mersad were partially due to their decision to establish a unified command structure and permanently quash the differences between the Army and the Revolutionary Guard.
Under pressure from other Arab states Saddam and MEK did not launch any more attacks on Iran. Operation Mersad was the last battle of the Iran–Iraq War.
The last notable combat actions of the war took place on 3 August 1988, in the Persian Gulf when the Iranian navy fired on a freighter and Iraq launched chemical attacks on Iranian civilians, killing an unknown number of them and wounding 2,300.
Both sides eventually withdrew to the international border in the coming weeks, with Resolution 598 becoming effective on 8 August 1988, ending all combat operations between the two countries. By 20 August 1988, peace with Iran was restored. UN peacekeepers belonging to the UNIIMOG mission took the field, remaining on the Iran–Iraq border until 1991. While the war was now over, Iraq spent the rest of August and early September clearing the Kurdish resistance. Using 60,000 troops along with helicopter gunships, chemical weapons (poison gas), and mass executions, Iraq hit 15 villages, killing rebels and civilians, and forced tens of thousands of Kurds to relocate to forced settlements. Many Kurdish civilians immigrated to Iran. By 3 September 1988, the anti-Kurd campaign ended, and all resistance had been crushed. 400 Iraqi soldiers and 50,000 Kurdish civilians and soldiers had been killed. 
At least in part as a response to the invasion, Iran executed several thousand political prisoners across the country for treason, mainly members of the MEK, but even also some members of the Tudeh Party (Communist Party) and other opposition groups. The estimates for number of executions vary from as little as 1,400 to as high as 20,000. The most likely number was given by dissident Ayatollah Hussein-Ali Montazeri, as being between 3,800–4,500.  The death toll may have been higher for those MEK executed by frontline court-martials or dying in prison.
- "The Cult of Rajavi" by Elizabeth Rubin. New York Times, 13 July 2003
- Memories of a slaughter in Iran
- Khomeini fatwa 'led to killing of 30,000 in Iran'
- Farrokh, Kaveh. Iran at War: 1500–1988. Oxford: Osprey Publishing. ISBN 9781780962214.
- Hiro, Dilip, The Longest War, (1999), pp. 246–47
- Iranian party demands end to repression
- Massacre 1988 (Pdf)