Palestinian television reported on Saturday that 200 people were killed in an Israeli strike on an UNRWA school housing people who were displaced from the Jabalia refugee camp in northern Gaza.
The head of the UN Palestinian refugee agency (UNRWA) said on Saturday it had received "horrifying" images and footage of scores of people killed and injured in an attack on the al-Fakhoura school.
"These attacks cannot become commonplace, they must stop. A humanitarian ceasefire cannot wait any longer," UNRWA Commissioner-General Philippe Lazzarini said on social media platform X.
Social media videos -- which AFP was unable to immediately verify -- showed bodies covered in blood and dust on the floor of a building, where mattresses had been wedged under school tables in Jabalia, the Palestinian territory's biggest refugee camp.
Israel has vowed to destroy Hamas in response to the October 7 attacks which Israeli officials say killed about 1,200 people, most of them civilians in southern Israel, and saw about 240 people taken hostage.
The army's relentless air and ground campaign has since killed 12,000 people, including 5,000 children, according to the Hamas government which has ruled Gaza since 2007.
According to UN figures, some 1.6 million people have been displaced inside Gaza by six weeks of fighting.
A separate strike Saturday on another building in Jabalia camp killed 32 people from the same family, 19 of them children, the official said. The ministry released a list of 32 members of the Abu Habal family it said had died.
Contacted by AFP, the Israeli army did not immediately respond to requests for comment on the two strikes.
Israel has told Palestinians to move from north Gaza for their safety, but deadly air strikes continued to hit central and southern areas of the narrow coastal territory.
On Saturday hundreds of people fled on foot after the director of Gaza's main hospital said the Israeli army ordered evacuation of the facility where some 2,000 people were trapped.
Columns of sick and injured -- some of them amputees -- were seen making their way out of Al-Shifa hospital towards the seafront without ambulances along with displaced people, doctors and nurses, as loud explosions were heard around the facility.
On the way, an AFP journalist saw at least 15 bodies, some in advanced stages of decomposition, along a road lined by badly damaged shops and overturned vehicles, as Israeli drones buzzed overhead.
The Hamas-run health ministry said 120 wounded, along with an unspecified number of premature babies, were still at Al-Shifa hospital that has become the focus of the recent fighting.
Israel has been pressing military operations inside the hospital, searching for the Hamas operations center it says lies under the sprawling complex -- a charge Hamas denies.
'Patients cannot leave'
In Gaza City, Israeli troops had called over loudspeakers to evacuate Al-Shifa "in the next hour", an AFP journalist at the hospital reported.
They also called the hospital's director, Mohammed Abu Salmiya, telling him to ensure "the evacuation of patients, wounded, the displaced and medical staff, and that they should move on foot towards the seafront", he said.
But Israel's army denied ordering the evacuation, saying instead it had "acceded to the request of the director" to allow more civilians to leave.
According to Ahmed El Mokhallalati, a doctor at the hospital, "most of the medical staff and patients had left" but he was staying at Al-Shifa along with five other doctors.
Despite the evacuation order, "many patients cannot leave the hospital as they are in the ICU beds or the baby incubators," Mokhallalati said on X, formerly Twitter.
The United Nations estimated 2,300 patients, staff and displaced Palestinians were sheltering at Al-Shifa before Israeli troops entered it on Wednesday.
Israel has imposed a siege on Gaza, allowing just a trickle of aid in from Egypt but barring most shipments of fuel over concerns Hamas could divert supplies for military purposes.
A first consignment of fuel entered Gaza after Israel's war cabinet bowed to pressure from its ally the United States and agreed to let in two diesel tankers a day.
Fuel 'when hostages are released'
A two-day blackout caused by fuel shortages ended after a first delivery arrived from Egypt late Friday, but UN officials continued to plead for a ceasefire, warning no part of Gaza is safe.
A strike on a residential building in southern Gaza killed 26 people, the director of the Nasser hospital in Khan Yunis said.
"I was asleep and we were surprised by the strike. At least 20 bombs were dropped," Imed al-Mubasher, 45, told AFP.
His wife Sabrin Mussa said she "saw human remains everywhere" and screamed for help.
The UN said Israel had agreed to allow in 60,000 liters (16,000 gallons) of fuel daily from Egypt starting Saturday, but warned it was little more than a third of what is needed to keep hospitals, water and sanitation facilities running.
Thomas White of UNRWA said Israel had "only permitted 50 percent of the daily fuel requirement for lifesaving humanitarian aid".
US President Joe Biden's chief adviser for the Middle East said more fuel deliveries and a potential "significant pause" in the fighting both depend of the release of hostages.
"The surge in humanitarian relief, the surge in fuel, the pause... will come when hostages are released," Brett McGurk told a security conference in Bahrain.
Israel has come under scrutiny for targeting hospitals in north Gaza, but says the facilities are being used by Hamas -- a claim rejected by the group and medical staff.
More than half of Gaza's hospitals are no longer functional due to combat, damage or shortages, and people are waiting four to six hours for half the normal portion of bread.
The military says it has found rifles, ammunition, explosives and the entrance to a tunnel shaft at the Al-Shifa hospital complex, claims that cannot be independently verified.
Israeli Prime Minister Benjamin Netanyahu has said, without providing details, that there were "strong indications" hostages may have been held there.
Israel has not recovered hostages at the hospital but said it found not far away the bodies of two kidnapped women including a soldier.
