Amid stormy meetings and acrimonious disagreements over voting procedures, leaders of Fatah, the mainstream Palestinian nationalist movement, postponed elections for its decision-making bodies that were scheduled for Thursday. They said the landmark party conference taking place here would go on for at least two more days.

Fatah members are hoping that the conference, their first in 20 years, will revitalize and unify the troubled movement and fortify it against its Islamic rival, Hamas. But Fatah, at the vanguard of Palestinian efforts to negotiate peace deals with Israel, has been showing its more usual tendency for infighting and disarray.

Some delegates complained of bad planning, and observers described an atmosphere bordering on anarchy. But others said they were happy that the full spectrum of members’ opinions was finally being aired.

“I am proud,” said Saeb Erekat, a senior aide of Mahmoud Abbas, the Palestinian president and Fatah’s leader. “Are we fighting? You bet! Are we screaming at each other? You bet!”

Taisir Nasrallah, a delegate from the Balata refugee camp in Nablus, said he felt “overwhelming anger” among the members against the traditional leadership. He added that many delegates wanted the old leaders to be held accountable for Fatah’s failures, like the loss of Gaza to Hamas.

The conference opened on Tuesday and was supposed to last three days. But by Thursday, delegates were still mired in discussions on how to hold fair internal elections when hundreds of their counterparts were stuck in Gaza, prevented from leaving by Hamas.

Some of the younger generation of reformers, who are hoping to increase their power within the movement, complained that the traditional leaders had packed the conference with their own supporters at the last minute.

“They brought their relatives, their secretaries,” said Hussam Khader, a firebrand Fatah leader from Nablus who has long campaigned against corruption in the movement.

Others dismissed the complaints as electioneering.

One point of consensus reached on Thursday was the notion that Israel was responsible for the death of Yasir Arafat, the Palestinian leader and Fatah founder, who died in 2004. In the convention hall, delegates blamed Israel for having kept the ailing Mr. Arafat under siege in his headquarters in the West Bank. Fatah officials said they would continue to investigate the circumstances of his death, and suspicions that Israel poisoned him.

Delegates have come to Bethlehem from as far as Yemen and the United States. They include people as diverse as Sari Nusseibeh, an intellectual from Jerusalem who has championed nonviolence, and Khaled Abu Asba, who took part in a notorious attack in 1978 in which an Israeli bus was hijacked and about three dozen Israeli civilians were killed.

Separately, Human Rights Watch, based in New York, released a report on Thursday stating that Hamas rocket attacks from Gaza against civilian areas in Israel were unlawful and amounted to war crimes.

The rocket fire led Israel to mount a deadly three-week campaign against Hamas in Gaza that ended in mid-January. Since then, the rocket fire has decreased sharply, but Hamas has not renounced the use of rockets.