UN rights chief condemns Israeli 'siege' of Gaza

Israeli retaliatory air strikes against Hamas  group struck residential buildings and schools across the Gaza Strip, UN Human Rights chief Volker Turk said on Tuesday, adding that "sieges" were illegal under international law.

Turk also condemned "horrifying mass killings by members of Palestinian armed groups" and said the fighters' abduction of hostages was also forbidden under international law.

The Israeli military said on Monday it had called up an unprecedented 300,000 reservists and was imposing a total blockade of the Gaza Strip, in a sign it may be planning a ground assault in response to the devastating weekend attacks by Hamas gunmen.

Israel's air attacks - the worst in the 75-year history of its conflict with the Palestinians - also hit "premises of the UN relief and works agency, UNRWA (UN Palestinian refugee agency)," a UN rights office statement said, adding that civilians were among the dead and injured.

Israel vowed to take "mighty revenge" after the Hamas attack left its streets strewn with bodies. Israeli media said 900 people were killed in the attacks and most were civilians, while nearly 700 Gazans were killed in Israeli strikes, according to Gaza officials, with entire districts in Gaza flattened.

Israel's defence forces said on social media platform X that aircraft had hit military targets, including weapons storage and manufacturing sites.

Turk said Israel's "imposition of sieges that endanger the lives of civilians by depriving them of goods essential for their survival is prohibited under international humanitarian law".

"This risks seriously compounding the already dire human rights and humanitarian situation in Gaza, including the capacity of medical facilities to operate, especially in light of increasing numbers of injured," he said, adding that a siege may amount to "collective punishment".

Read also: Israel imposes 'total blockade' on Gaza as aircraft continue to pound enclave

Such acts may amount to a war crime, UN Human Rights spokesperson Ravina Shamdasani later clarified. The UN rights office's findings were based on a review of available material, including from its own monitors on the ground, she said.

Separately, a UN -appointed Commission of Inquiry said in a statement there was already "clear evidence that war crimes may have been committed" by all sides to the conflict. It said it was collecting evidence to ensure future legal accountability.

Some 187,500 people have fled their homes in Gaza, a UN humanitarian office offices spokesperson said at the same briefing, warning of shortages of water and electricity.

"UNICEF is extremely alarmed about measures to cut electricity, to cut food, to cut water to cut fuel from entering Gaza. This will add another layer of suffering to the existing catastrophe faced by families in Gaza," said UN children's agency spokesperson James Elder. He added that "hundreds" of Israeli and Palestinian children had been killed since the weekend, without giving details.

World Health Organization's Tarik Jašarević said that 13 attacks on health facilities in Gaza had been confirmed by its monitoring service since hostilities began.

It was working on a humanitarian corridor for the Gaza strip, but stores of medical supplies had already run out, he said.