The report accuses Israel of using "disproportionate force" in Gaza
UN investigator Richard Goldstone has defended his damning report on Israel's conduct in during its operation Gaza.
As the UN human rights watchdog debated the report, which accused Israel and Hamas of war crimes, he rejected what he called a "barrage of criticism".
A US official dubbed the report "deeply flawed". Israel dismissed it as biased.
Separately, a UK court has rejected an attempt by a Palestinian group to have Israeli Defence Minister Ehud Barak arrested for alleged war crimes.
Under the principle of universal jurisdiction, war crimes suspects can be tried in British courts. But the British court ruled that Mr Barak had diplomatic immunity.
A slew of critical reports have raised concerns that Israel and Palestinian militants may have committed war crimes during the 22-day Israeli offensive in Gaza.
The Goldstone report, widely lauded by human rights groups, accuses both Israel and its militant Palestinian adversary Hamas of war crimes in the campaign.
Mr Goldstone rejected what he called a "barrage of criticism" about his findings and public attacks against the members of his mission.
"We will not address these attacks as we believe that the answers to those who have criticised us are in the findings of the report," he said.
Human Rights Watch criticised the failure of either the US or the European Union to endorse the report as "a message that serious laws-of-war violations will be treated with kid gloves when committed by an ally".
The 574-page report was written by a four-judge commission led by South African judge Richard Goldstone.
It accused both the Israeli army and Palestinian militants of deliberately terrorising and killing civilians on the other side.
It urged the UN Security Council to refer allegations to the International Criminal Court (ICC) if either side failed to investigate and prosecute suspects.
The US had already rejected recommendations regarding the UN Security Council, saying it should not even discuss the matter.
Israel refused to co-operate with investigations and has rejected the findings as "flawed" and "biased".
The debate was seen as a test of US engagement with the Human Rights Council, which was shunned by President George W Bush.
Human Rights Watch, one of a number of NGOs that endorsed the report, has urged the administration to reverse its position.
"The Obama administration cannot demand accountability for serious violations in places like Sudan and Congo but let allies like Israel go free," said HRW's Sarah Leah Whitson.
The enquiry found evidence "indicating serious violations of international human rights and humanitarian law were committed by Israel during the Gaza conflict".
Israel's operations, the document states, "were carefully planned in all their phases as a deliberately disproportionate attack designed to punish, humiliate and terrorise a civilian population".
The report also found evidence Palestinian groups committed war crimes, and possibly crimes against humanity, in repeated indiscriminate rocket and mortars attacks on Israel.
Israeli Ambassador Aharon Leshno-Yaar said the report was "shameful", claiming it cherry-picked incidents for political effect, ignoring Israel's right to defend itself.
Hamas called the report "political, biased and dishonest" as it put people "who resist" crimes "on the same level as those who perpetrate" them.
The Israeli military has carried out more than 100 investigations into allegations of abuses by in Gaza. Most were dismissed as "baseless" but 23 criminal investigations are still ongoing.
The Human Rights Council was founded three years ago, after criticism of its predecessor that it turned a blind eye to many human rights abuses while having an in-built anti-Israel bias.
The Bush administration took no part in the new body, but the Obama administration sought a seat on the council after it came to power in January.