United Nations chief Antonio Guterres has incensed Israel after suggesting that the brutal Hamas attacks on October 7 “did not happen in a vacuum”.

Israel on Wednesday morning (AEDT) demanded Guterres’s resignation and Foreign Minister Eli Cohen asked: “Mr Secretary-General, in what world do you live? Definitely this is not our world.”

At a fiery meeting of the UN Security Council, Guterres said he was “deeply concerned” about humanitarian law being broken in the conflict between Israel and Hamas.

Without naming either side, the UN leader spoke of civilians being used as “human shields” and hundreds of thousands of people being left without basic needs.

“Protecting civilians can never mean using them as human shields,” he said.

“Protecting civilians does not mean ordering more than one million people to evacuate to the south, where there is no shelter, no food, no water, no medicine and no fuel, and then continuing to bomb the south itself.”

Hundreds of Palestinian children are being killed and injured in Gaza. Photo: Getty

The UN has warned that its humanitarian operation will be forced to end in the next day without fuel supplies entering Gaza which is under a total Israeli blockade.

More than 40 medical centres halted operations after they ran out of fuel or were damaged by Israeli bombing, a Gaza health ministry spokesman said.

Palestinians suffered the highest 24-hour death toll of the siege to date, with more than 700 killed overnight by Israeli air strikes, said Gaza’s Hamas-run health ministry.

Earlier, one of two elderly female hostages released by Hamas on Tuesday (AEDT) spoke of her hellish experience, but also mentioned the “caring” nature of her captors.

Hostage describes ‘hell’

Yocheved Lifshitz, 85, said she beaten with a cane across her ribcage as she was abducted and driven away on a motorbike.

“They stormed into our homes. They beat people. They kidnapped others, the old and the young without distinction,” she said, seated in a wheelchair and speaking in barely a whisper.

“I went through hell, that I could not have known”.

Inside Gaza, a group of hostages were led into what Lifshitz called a “spider’s web” of damp tunnels.

They eventually reached a large hall where, under 24-hour guard, a doctor visited every other day and brought them medicines.

“They treated us gently and met all our needs,” she said during a chaotic media conference that Israeli commentators said was a PR win for Hamas.

More than 200 hostages were taken during the Hamas rampage when 1400 people were killed.

Yocheved Lifshitz, one of the two freed hostages, speaks to media in front of Ichilov Hospital. Photo: Getty

Gaza’s health ministry said at least 5791 Palestinians have been killed by Israeli bombardments of the densely populated territory since October 7, including 2360 children.

After an air strike in Khan Younis, Abdallah Tabash held his dead daughter Sidra, refusing to let go as he held her bloodstained face and hair.

“I want to look at her as much as I can,” he said.

Doctors in Gaza say patients arriving at hospitals are showing signs of disease caused by overcrowding and poor sanitation after more than 1.4 million people fled their homes for temporary shelters under Israel’s heaviest-ever bombardment.

United Nations agencies called “on our knees” on Tuesday for emergency aid to be allowed unimpeded into Gaza, saying more than 20 times current deliveries were needed to support its Palestinian population after two weeks of Israeli bombardment.

The World Health Organisation, in the latest of increasingly desperate UN appeals, called for “an immediate humanitarian ceasefire” to allow safe deliveries of aid.

But there appeared to be little prospect of a ceasefire any time soon in the bloodiest episode in the Israeli-Palestinian conflict for decades.

Israeli tanks and troops are massed on the border between Israel and the enclave awaiting orders for an expected ground invasion – an operation that may be complicated by fears for the hostages’ welfare and militants dug into a crowded urban setting using a vast network of tunnels.

Israeli soldiers are awaiting orders for an expected ground invasion of the Gaza Strip.

The bombardments were unleashed in response to a shock cross-border Hamas assault into southern Israel in which gunmen killed more than 1400 people – mostly civilians – in a single day.

Among the targets Israel said it hit overnight was a tunnel that allowed Hamas to infiltrate Israel from the sea, as well as Hamas command centres in mosques, it said.

Reuters could not verify the report.

Wide areas of highly urbanised Gaza have been demolished by Israeli bombs, forcing more than half of its 2.3 million people to seek shelter elsewhere in the territory.

-with AAP