Hamas warned Sunday that no hostages would leave Gaza alive unless its demands for prisoner releases are met, while the World Health Organization said the territory's health system is collapsing after more than two months of war.
Hamas triggered the conflict with the deadliest-ever attack on Israel on October 7 in which it killed some 1,200 people, according to Israeli figures, and dragged around 240 hostages back to Gaza.
Israel has responded with a relentless military offensive that has reduced much of Gaza to rubble and killed at least 17,997 people, mostly women and children, according to the Hamas-run health ministry.
As aid groups warn the territory is on the brink of being overwhelmed by disease and starvation, the head of the United Nations decried a divided and "paralysed" Security Council for failing to agree on a ceasefire.
"Gaza's health system is on its knees and collapsing," said World Health Organization chief Tedros Adhanom Ghebreyesus, with only 14 of 36 hospitals functioning at any capacity.
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The United Nations estimates that 1.9 million of Gaza's 2.4 million people have been displaced -- roughly half of them children -- many forced south and running out of safe places to go.
"We have been stuck here for 18 days. Whenever I want to go somewhere, we hear bombing and shelling and feel scared and go back," said Noura al-Sayed Hassan, trapped in Rafah despite having an Egyptian passport.
"I've been searching for bread for my daughter for over a week now."
The UN humanitarian agency OCHA said only 100 aid trucks entered Gaza via the Rafah crossing with Egypt on Saturday, well below the pre-war average.
"The restrictions and challenges being placed on the delivery of lifesaving aid... are another death sentence for children."
'Not human beings'
Hamas said Sunday that Israel had launched "very violent raids" targeting the biggest southern city of Khan Yunis and the road linking it to Rafah near the border with Egypt.
"Neither the fascist enemy and its arrogant leadership... nor its supporters... can take their prisoners alive without an exchange and negotiation and meeting the demands of the resistance," Hamas spokesman Abu Obeida said in a televised broadcast.
There are still 137 hostages held in Gaza, according to Israel. Activists say around 7,000 Palestinians are detained in Israeli jails, and senior Hamas official Bassem Neim said in late November that the movement was "ready to release all soldiers in exchange for all our prisoners".
On Sunday a source close to Hamas and Islamic Jihad told AFP both groups were engaged in "fierce clashes" with Israeli forces near Khan Yunis, where an AFP journalist also reported heavy strikes, as well as Jabalia and Gaza City's Shejaiya district in the north.
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Prime Minister Benjamin Netanyahu said Israel would continue its "just war to eliminate" Hamas, while army chief Herzi Halevi urged his forces to "press harder" in their offensive.
The army said it struck more than 250 targets in 24 hours, it said Sunday, including "a Hamas military communications site" and "underground tunnel shafts" in southern Gaza, as well as a Hamas military command centre in Shejaiya.
It says 98 soldiers have died in the Gaza campaign and around 600 wounded have been evacuated.
Some 7,000 "terrorists" have been killed, according to National Security Adviser Tzachi Hanegbi.
Senior Israeli military officials, speaking on December 4, were asked about media reports that 5,000 Hamas fighters had been killed. That figure is "more or less right," one of the officials said.
"Hamas should not exist, because they are not human beings, after what I saw they did," Menahem, a 22-year-old soldier injured on October 7, told AFP during a military-organised tour that did not allow him to give his surname.
'UN credibility undermined'
UN Secretary-General Antonio Guterres said the Security Council's "authority and credibility were severely undermined", after the United States on Friday blocked a ceasefire resolution.
"I can promise, I will not give up," Guterres told Qatar's Doha Forum.
Qatar said it was still working on a fresh truce, but that Israel's relentless bombardment was "narrowing the window" for success.
The Gulf emirate, where Hamas's top leadership is based, was a key mediator for a seven-day truce last month that saw 80 Israeli hostages exchanged for 240 Palestinian prisoners and humanitarian aid.
Hundreds of Israelis rallied for the hostages on Saturday in Tel Aviv, holding placards reading "Bring them home now" and "They trust us to get them out of hell".
Israel launched a failed rescue operation late Thursday. Hamas said a captive was killed in the operation. The death of Sahar Baruch, 25, was later confirmed by his community of Beeri, one of the worst hit on October 7
