"We remain convinced that the Palestinian people are at grave risk of genocide," the experts said in a joint statement.

"The time for action is now. Israel's allies also bear responsibility and must act now to prevent its disastrous course of action."

UN special rapporteurs are unpaid, independent figures mandated by the Human Rights Council. They do not speak for the United Nations but report their findings to it as part of the council's fact-finding and monitoring mechanisms.

"The situation in Gaza has reached a catastrophic tipping point," the experts said, warning of the "dire need" for food, water, medicine, fuel and essential supplies and the risk of looming health hazards.

The statement was signed by Francesca Albanese, special rapporteur on the situation of human rights in the Palestinian territory occupied since 1967.

The other signatories were the special rapporteurs on safe drinking water; food; physical and mental health; internally displaced persons; freedom of expression; and on contemporary racism.

More than 9,000 Palestinians, two-thirds of them women and children, have been killed in relentless bombardment on the Gaza Strip, according to Palestinian health ministry figures.

The UN experts called for the immediate release of all civilians held captive by Hamas.

"All parties must comply with their obligations under international humanitarian and human rights law," they said.

"We demand a humanitarian ceasefire to ensure that aid reaches those who need it the most. A ceasefire also means channels of communication can be opened to ensure the release of hostages," the experts said.

Gaza's government said 195 people were killed in two days of Israeli strikes on Jabalia, Gaza's largest refugee camp, with hundreds more missing and wounded -- figures AFP could not independently verify.

The UN experts voiced "deepening horror" about the strikes, calling them "a brazen violation of international law -- and a war crime".

"Attacking a camp sheltering civilians including women and children is a complete breach of the rules of proportionality and distinction between combatants and civilians," the special rapporteurs said.

"Israel and Palestinian armed groups must bear in mind that even wars have rules."

*This story was edited by Ahram Online