The Tanzim militia, founded in 1995 by Yasser Arafat and other Fatah leaders to counter Palestinian Islamism, is widely considered to be an armed offshoot of Fatah with its own leadership structure. The acknowledged head of the Tanzim is Marwan Barghouti, who is as of 2010, serving five consecutive life sentences in Israel for murder, and, according to some accounts, has a substantial following among the “rejectionist” camp which opposes the Interim Agreement (also called Oslo II or Taba) signed on 28 September 1995 with Israel.
The Tanzim is a grass roots organization that operates at the community level. By taking a hardline position against Israel, it has helped siphon Palestinian support from the Islamist groups to the Palestinian Authority and PLO leadership. 
Tanzim came to prominence in the street fighting which marked the beginning of the second Palestinian Intifada. Its members tend to be younger than those of other Fatah factions, often having grown up in the post-Oslo era. Many Tanzim members have joined the al-Shaid Yasser Arafat Brigades (formerly the al Aqsa Martyrs' Brigades). Tanzim has also recruited female suicide bombers, including Andaleeb Takatka, a 20-year-old Bethlehem woman who detonated an explosive belt at a Jerusalem bus stop in April 2002, killing six Israeli civilians, and injuring sixty. Marwan Barghouti, widely described as heading Tanzim, explicitly condemned terror attacks within Israel, writing "While I, and the Fatah movement to which I belong, strongly oppose attacks and the targeting of civilians inside Israel, our future neighbor, I reserve the right to protect myself, to resist the Israeli occupation of my country and to fight for my freedom."
- "Palestinian Organizations". Arab Gateway. Retrieved 18 November 2012.
- This article incorporates public domain material from the Congressional Research Service document "Palestinian Factions".
- Citation needed
- Fatah Tanzim at GlobalSecurity.org