Palestinian Authority leaders co-operated with US officials in a bid to postpone the reference of the Goldstone report into war crimes in Gaza to the UN security council, leaked papers reveal. The PA, who have denied they made the decision under US pressure, later reversed their decision.

The postponement of the report into Israel's 2008 assault on Gaza triggered heavy criticism of the PA leadership, at one time threatening Abbas's position. But at a meeting on 21 October 2009, three weeks after the Goldstone scandal erupted, US national security adviser Jim Jones told the Palestinian negotiator Saeb Erekat: "Thank you for what you did a couple of weeks ago [on Goldstone]; it was very courageous".

On the day the reference of the report was delayed, US officials presented Palestinian negotiators with a "non paper" [a proposal that is off the record in diplomatic terms] committing the PA to "help promote a positive atmosphere conducive to negotiations ... [and] refrain from pursuing or supporting any initiative directly or indirectly in international legal forums that would undermine that atmosphere".

Erekat's response was to tell Mitchell: "On going to the UN we will always co-ordinate with you."

The papers also reveal new evidence of contact between Mahmoud Abbas, also known as Abu Mazen, the Palestinian president, and Amos Gilad, a senior Israeli defence ministry official and senior negotiator, before the the launch of Israel's assault in late 2008. It remains unclear whether he had advance warning of the impending assault, which he has always denied.

Contacted by Gilad before the war, "Abu Mazen replied that he will not go to Gaza on an Israeli tank," the Palestinian negotiator Saeb Erekat told the US envoy George Mitchell in October 2009.

Any evidence that PA leaders co-operated with Israel in the attack on the Hamas-controlled territory, which left 1,400 Palestinians dead, would be highly controversial and fuel anger at the western-backed Ramallah-based leadership, especially by its bitter rival, Hamas.

Earlier this week, Gilad publicly and flatly denied the collusion claim. "No concrete warning concerning an offensive was given to the Palestinian Authority," he told Israel Radio.

"I didn't say anything to President Abbas that I hadn't said to the entire world: that we could not tolerate the resumption of rocket fire and other terrorist attacks against our territory."

Abbas issued a forceful denial late last year when US diplomatic cables released by Wikileaks were quoted as reporting that in June 2009 Israel's defence minister, Ehud Barak, told a US congressional delegation that Israel "had consulted with Egypt and Fatah prior to Operation Cast Lead, asking if they were willing to assume control of Gaza once Israel defeated Hamas." Barak continued: "Not surprisingly...Israel received negative answers from both."

Erekat said at the time:"Nobody consulted with us, and that is the truth. Israel doesn't consult before going to war."

The Palestine Papers also record how Gilad and Tzipi Livni, then Israeli foreign minister, had spoken to Palestinian negotiators of the likelihood of a fullscale confrontation over Gaza. "We are on a collision course with Hamas," Gilad warned them. "You need to be prepared.. Sooner or later they [Hamas] will be taken care of."