Dozens of nations at the UN have backed a non-binding resolution calling for independent inquiries by Israel and the Palestinians into war crimes in Gaza.
The UN General Assembly is set to vote on the resolution at the end of a two-day debate on a report by former war crimes prosecutor Richard Goldstone.
The report condemns the conduct of both sides last December and January, after Israel launched an offensive in Gaza.
The Palestinians support the debate but Israel says it does not promote peace.
Mr Goldstone's report concluded that Israel had "committed actions amounting to war crimes, possibly crimes against humanity" by using disproportionate force, deliberately targeting civilians, using Palestinians as human shields and destroying civilian infrastructure during its Gaza offensive.
It also found there was evidence that Palestinian militant groups including Hamas, which controls Gaza, had committed war crimes, and possibly crimes against humanity, in their repeated rocket and mortars attacks on southern Israel.
The report demanded that unless the parties to the Gaza war investigated the allegations of war crimes within six months, the cases should be referred to the International Criminal Court.
Palestinians and rights groups say more than 1,400 Gazans died in the 22-day conflict, but Israel puts the figure at 1,166. Thirteen Israelis, including three civilians, were killed.
'Realisation of justice'
The General Assembly draft resolution has been introduced by Arab states and the Non-Aligned Movement, which represents 118 nations.
It calls for independent investigations of alleged war crimes to be set up by both the Palestinian Authority and Israel within three months.
The resolution also asks Secretary General Ban Ki-moon to report to the General Assembly within three months on implementation "with a view to considering further action, if necessary, by the relevant United Nations organs and bodies", and to send the report to the Security Council.
General Assembly resolutions are not legally binding – unlike Security Council resolutions. However, correspondents say the Security Council is unlikely to take any action if the case is ever referred to it.
Riyad Mansour, the Palestinian UN observer, backed the resolution but also insisted that Israel's "aggressions and crimes" could not be equated "with actions committed in response by the Palestinian side".
"We are determined to follow up this report and its recommendations in all relevant international forums, including the Security Council and the International Criminal Court, until the realisation of justice," he said.
Israel's permanent representative, Gabriela Shalev, warned that the report and the debate did "not promote peace – they damage any effort to revitalise negotiations in our region".
"Time and again, the report inverts Israel's unprecedented extensive efforts to save civilian lives as proof that any civilian casualties were therefore deliberate," she told the Assembly.
The US, as a key ally of Israel, was one of a small number of countries expected to vote against the resolution.
For the EU, Sweden's UN envoy Anders Liden urged Israel and the Palestinians to "launch appropriate, credible and independent investigations into possible violations".
He described the report as "serious" and said the EU was "committed to assessing it seriously".
The UN debate also comes as an Israeli human rights organisation criticised investigations being carried out by the Israeli military.
B'tselem said 13 of 23 military police investigations under way were based on information it and two other rights organisations had gathered.
Three of the cases concerned civilians allegedly killed while holding white flags, and four were cases where Gazans were said to have been used as human shields.
B'tselem said the investigations were not sufficient because they "only relate to isolated incidents in which a suspicion exists that soldiers breached military orders".
"To date, not one investigation has been opened regarding Israel's policy during the operation, on matters such as the selection of targets, the open-fire orders given to soldiers, the legality of the weapons used, the balance between injury to civilians and military advantage, and so forth," it said.