Reports of hundreds of fatalities from bombing in southern Gaza over the weekend heightened deep concerns for civilians sheltering there, while UN humanitarians on Monday said that aid teams had only "extremely limited" movement and access to the north was "now entirely blocked".
The latest update from the UN aid coordination office, OCHA, confirmed rising casualties and devastation amid "heavy Israeli bombardment from air, land and sea".
"From the afternoon of (Saturday) 2 December to the afternoon of (Sunday) 3 December, at least 316 people were killed and at least another 664 injured in Gaza," OCHA's situation update reported, adding that an Israeli soldier had been reportedly killed in the enclave at the weekend and another had succumbed to wounds sustained previously.
The return to bloodshed followed the breakdown of a ceasefire between Hamas and Israel last Friday, 1 December, that had allowed for the release of dozens of the approximately 240 hostages taken from southern Israel during the group's terror attack that claimed some 1,200 lives, according to Israeli authorities, and of Palestinian prisoners held in Israel.
Health authorities in Gaza claim that more than 15,000 people have been killed since 7 October.
Nowhere is safe
Echoing humanitarians' concerns for civilians caught up in the violence, the UN agency for Palestinian refugees, UNWRA, said that in Rafah city in the south people were being forced to flee against a backdrop of airstrikes.
"People are pleading for advice on where to find safety," said Director of UNRWA Affairs Thomas White. "We have nothing to tell them."
Some 1.8 million Gazans now live in the south of Gaza after an order from the Israeli Defense Forces to residents to leave the north of the Strip in mid-October.
In a new development, OCHA reported that the Israeli military had "designated an area covering about 20 per cent of Khan Younis city for immediate evacuation" on Sunday, and that this area had been "marked in an online map (and) published on social media".
Prior to the onset of hostilities, this area was home to nearly 117,000 people, the UN aid coordination office said, noting that it housed 21 shelters with about 50,000 internally displaced persons (IDPs), the vast majority previously displaced from the north.
Critical aid still rolling in
Meanwhile, OCHA reported that some lifesaving humanitarian supplies were continuing to roll into Gaza late on Sunday evening from Egypt, although their exact number and contents were unclear. Ten humanitarian staff also entered via the Rafah border crossing, which also saw the evacuation of 566 foreign nationals and dual citizens, 13 injured people and 11 companions.
Security Council meets
In a sign of widespread international alarm over the continuing violence in Gaza, the UN Security Council was due to hold closed consultations on the issue on Monday.
The meeting, which was expected to feature Under-Secretary-General for Political and Peacebuilding Affairs Rosemary DiCarlo, was requested by the United Arab Emirates (UAE), which expressed the "deeply concerning resumption of hostilities and the continuing dire humanitarian situation in the Gaza Strip".
Killing of children
Meanwhile, in a social media post revealing a panorama of smashed masonry, rescue workers and distressed youngsters in southern Gaza on Saturday, UN Children's Fund (UNICEF) spokesperson James Elder railed against "the endless killing of children" after a night of "utterly relentless bombardments".
Speaking from inside a shelter, the UN official turned his mobile phone camera to Khaled and Hannah, two infants sleeping side by side. "Please meet them and see them, pray that they'll be alive in a few days' time, "he said. "I feel like I'm running out of ways to describe the endless killing of children here."
