The UN human rights chief warned a special session of the Human Rights Council that human rights violations in Gaza and some reported incidents there might warrant prosecutions for war crimes.
"The vicious cycle of provocation and retribution must be brought to an end," Navi Pillay told the council, which was holding a special session on human rights violations in the Palestinian territory.
"Accountability must be ensured for violations of international law," she said, calling for "credible, independent and transparent investigations" as a first step.
"I remind this council that violations of international humanitarian law may constitute war crimes for which individual criminal responsibility may be invoked," she added.
But the council meeting ended without agreement on a resolution after failure to agree on the term of a condemnation of human rights abuses since the Israeli intervention in Gaza.
Draft resolution contested
The session is expected to decide on Monday whether or not to adopt a draft resolution tabled by Cuba, Egypt and Pakistan.
The text seeks the 47-member council\'s condemnation of the Israeli offensive and of the "grave human rights situation" in Gaza.
The draft resolution tabled late Friday underlined the civilian toll, especially in Gaza, and called for "the immediate cessation of Israeli military attacks" as well as an "end to the launching of crude rockets against Israeli civilians" in a concession to the European Union.
It also demanded that Israel "stop the targeting of civilians and medical facilities and staff" and that border crossings be reopened.
However the council remains deeply split and there was doubt whether an agreed text could emerge by Monday night. Some western countries see the draft as one-sided and said the resolution should condemn human rights violations by both sides and not simply call for a ceasefire.
Legal obligation of care during conflict
Pillay called for an independent investigation of the violence, stressing that Israel and Palestinian militants had an obligation under international humanitarian law to care for the wounded, and to protect ambulances, hospitals, health workers, schools, civilians as well as their homes.
The High Commissioner underscored calls for a ceasefire, warning that rocket attacks from the Gaza Strip on Israel and "retaliatory" air strikes by Israel forces were "unacceptable."
"The situation is intolerable," she said, warning that the overall conditions for civilians "constitute egregious violations of human rights."
But Pillay went further, enumerating more evidence of violations of international humanitarian law from the UN agencies and the International Committee of the Red Cross, after civilians and relief workers were killed or wounded during Israeli attacks.
UN ceasefire rejected
The meeting comes on the heels of the UN Security Council\'s near unanimous approval on Thursday of a resolution calling for an immediate ceasefire and the unimpeded provision throughout Gaza of humanitarian assistance.
However, Hamas later rejected that resolution, and Israel followed by rejecting a ceasefire.