Israel bombarded targets in Gaza on Saturday after the United States blocked an extraordinary United Nations bid for a ceasefire in the war with Hamas.

Aid groups say Gaza faces an "apocalyptic" humanitarian situation and is on the verge of being overwhelmed by disease and starvation.

At least 17,490 people, mostly women and children, have died in two months of fighting in the narrow territory, according to the latest figures from Gaza's health ministry.

Washington vetoed a UN resolution that would have called for a ceasefire on Friday, a move strongly condemned by the Palestinian Authority and Hamas, as well as humanitarian groups. 

As Israel continued to pound Gaza with air strikes, the Hamas ministry said 71 dead had arrived at Al-Aqsa hospital in Deir al-Balah alone over 24 hours, and 62 at Nasser hospital in the southern city of Khan Yunis. 

An AFP correspondent in Nasser hospital saw a child on a makeshift stretcher and others simply sitting on the floor waiting to receive care, while firefighters outside poured water onto the flames of a burning building partly destroyed by an Israeli strike.

Alexandra Saieh, of Save the Children, spoke of "maggots being picked from wounds and children undergoing amputations without anaesthetic".

The situation "is not just a catastrophe, it's apocalyptic," added Bushra Khalidi of Oxfam.

Israel has vowed to eradicate Hamas after its unprecedented attacks on October 7, when militants broke through Gaza's militarised border to kill about 1,200 people and seize hostages, 138 of whom remain captive, according to Israel.

'Into the abyss'

UN Secretary-General Antonio Guterres triggered the rare Security Council vote on a ceasefire by invoking a measure unused in decades, saying "the people of Gaza are looking into the abyss".

But the US vetoed the Security Council resolution, with envoy Robert Wood saying it was "divorced from reality" and "would leave Hamas in place, able to repeat what it did on October 7".

Israeli Foreign Minister Eli Cohen said a ceasefire would save Hamas "which is committing war crimes and crimes against humanity, and would enable it to continue ruling the Gaza Strip".

Palestinian president Mahmud Abbas said he "holds the United States responsible for the bloodshed of Palestinian children, women and elderly people" after the veto.

Avril Benoit, head of the Doctors Without Borders (MSF) charity, described the US veto as a "sharp contrast to the values it professes to uphold".

There was anger, too, in a residential area of Rafah decimated by an Israeli strike.

"What resolution did the Security Council ever approve and was implemented for our cause and Palestinian people?" local resident Mohammed al-Khatib said amid the rubble.

Hamas denounced the veto as "a direct participation with the occupation (Israel) in the killing of our people".

Iran, which backs Hamas, warned it could lead to an "uncontrollable explosion in the situation of the region", while Turkish President Recep Tayyip Erdogan denounced the UN body as the "Israel protection council".

'Apocalyptic' situation

An estimated 1.9 million of Gaza's 2.4 million people have been displaced. 

Blocked from leaving the narrow territory, they have turned Rafah near the crossing with Egypt into a vast camp.

One of only two partially operating hospitals in Gaza's north, Al-Awda, "is surrounded by Israeli troops and tanks, and fighting is ongoing in its vicinity", the UN said.

Nearby in Jabalia district, the soil in front of shuttered shops had been dug up and turned into a cemetery where men buried more bodies.

Washington, which provides billions of dollars in military aid to Israel, has urged its ally to do more to protect civilians.

"We're going to keep working with our Israeli counterparts to that end," said US National Security Council spokesman John Kirby.

Weapons 'in a school'

Israel says 93 of its soldiers have been killed in Gaza, and two others were severely injured in a failed bid to rescue hostages.

Hamas said a hostage, 25-year-old Sahar Baruch, was killed in the operation, later confirmed by his kibbutz community in Beeri, one of the worst-hit on October 7.

With air, naval and ground combat continuing, the military said troops found weapons "in a school" in Gaza City.

In Beit Hanun, close to the northern boundary with Israel, troops struck militants "who shot at them from an UNRWA school and a mosque", the military said, referring to the UN agency for Palestinian refugees.

Hamas's armed wing said it fired rockets towards Reim in southern Israel — the site of the Supernova music festival where 364 people were killed on October 7, according to Israeli figures.

Israel said rocket fire had come from a "designated humanitarian zone", saying Hamas was exploiting safe areas "for terrorist activity". 

There are fears of a wider regional conflict, with regular exchanges between Israel and Lebanon's Iran-backed Hezbollah movement.

Israel's army said it had retaliated on Saturday after unspecified "launches" from Lebanon, including with fighter jets.

Violence has also surged in the Israeli-occupied West Bank, where the military says it has arrested 2,200 people, 1,800 of them Hamas members, since the Israel-Hamas war began.