GENEVA - The Palestinian Authority, under heavy pressure from the United States, has withdrawn its support for a U.N. Human Rights Council resolution on alleged war crimes in Gaza, diplomats said Thursday.

The resolution endorses a U.N. report that claims both Israel and Palestinian militant groups committed war crimes and possible crimes against humanity during their Dec. 27-Jan. 18 conflict. Palestinian officials earlier this week welcomed the report when it was presented to the Geneva-based rights council, while Israel and the United States have strongly rejected the findings.

U.N. and European diplomats, who spoke on condition of anonymity because they were not authorized to discuss the matter with reporters, said the Palestinian delegation's surprise turnaround means any resolution on the report would likely be delayed until next March.

Although the Palestinians aren't voting members of the 47-nation rights council, Arab and Muslim countries who control the body may be reluctant to press ahead with the resolution Friday without Palestinian support.

A senior U.S. official, also speaking on condition of anonymity, said the Palestinian decision came after "intense diplomacy" by Washington to convince the Palestinian leadership that going ahead with the resolution would harm the Middle East peace process.

"The Palestinians recognized that this was not the best time to go forward with this," the U.S. official said.

Israeli Prime Minister Benjamin Netanyahu earlier Thursday warned the report would "strike a fatal blow against the peace process, because Israel will not be able to take additional steps and take risks for the sake of peace if denied its right to self-defence."

The report recommended that the U.N. Security Council in New York require both sides to show they are carrying out credible investigations into alleged abuses during the three-week conflict -- in which almost 1,400 Palestinians and 13 Israelis were killed.

U.N. experts, led by former South African judge Richard Goldstone, examined 36 incidents and interviewed dozens of Palestinian and Israeli witnesses in Gaza and Geneva to compile the report.

The incidents include one case in which Israeli forces allegedly shelled a house where soldiers had forced Palestinian civilians to assemble, and seven incidents in which civilians were shot while leaving their homes trying to run for safety.

On the Palestinian side, the report found that armed groups firing rockets into southern Israel from Gaza failed to distinguish between military targets and the civilian population, and several allegations that Palestinians were held as human shields by militants.