Marwan Barghouthi, serving a life sentence in an Israeli jail, was elected to a leading post in Palestinian President Mahmoud Abbas's Fatah faction on Tuesday, initial results showed.

Barghouthi was jailed on charges of organising the killing of Israelis. He denies the charges.

Some members of the Fatah "Old Guard" lost their positions when the faction elected a new top executive body, the initial results showed after more than 90 percent of votes had been counted for the 18-member Central Committee.

Abbas has said the party, holding its first congress in 20 years, needed to show disillusioned voters a new beginning.

Out of 10 "Old Guard" members seeking re-election, less than half succeeded.

The movement headed by the late Yasser Arafat for 40 years wants to shed a reputation for corruption and cronyism that led in 2006 to a stunning election loss to its Islamist rival Hamas, which opposes peace with Israel.

Hamas seized the Gaza Strip in a civil war a year later, splitting the Palestinian independence movement.

The Fatah congress began last Tuesday with about 2,000 delegates attending in the West Bank town of Bethlehem. Most of its proceedings have been held behind closed doors.

Abbas, 74, was reaffirmed unopposed as leader in a show of hands that made it impossible to tell if anyone voted against him.

However, critics say he is weak and that the congress may not strengthen his position.

Fatah is ready to negotiate a peace deal with Israel but it is struggling to reverse a decline in popularity. Abbas has no vice-president and no natural successor waiting in the wings.

Barghouti, 50, is a popular and articulate figure who was once seen as a successor to Arafat.

A controversial figure who won a post was Mohammed Dahlan, reviled by Hamas supporters over crackdowns he led against the Islamist group when he headed the Fatah-dominated Preventive Security service in the Gaza Strip in the 1990s.