DEIR AL-BALAH, Gaza Strip (AP) — An Israeli attack on a school in central Gaza that houses displaced Palestinians killed more than 30 people early Thursday, including 23 women and children, local health officials said. The Israeli military said Hamas militants were operating from the school.

It was the latest case of mass casualties among Palestinians seeking refuge as Israel escalates its offensive. A day earlier, the military announced a new ground and air assault on central Gaza to pursue Hamas fighters it said had regrouped there. Troops have repeatedly returned to parts of the Gaza Strip they previously occupied, underscoring the militant group's resilience despite Israel's nearly eight-month onslaught.

Witnesses and hospital workers said the early morning attack hit the al-Sardi school, run by the UN Relief and Works Agency for Palestine Refugees (UNRWA). The school was full of Palestinians fleeing Israeli operations and bombings in northern Gaza, they said.

Ayman Rashed, a man displaced from Gaza who had sought shelter in the school, said the rockets hit classrooms on the second and third floors where families had sought shelter. He said he helped carry out five dead bodies, including an old man and two children, one of whom had a smashed head. “It was dark, there was no electricity and we struggled to get the victims out,” Rashed said.

Victims of the school strike arrived at the Al-Aqsa Martyrs' Hospital in nearby Deir al-Balah, which had already been overwhelmed by a steady stream of ambulances since the incursion into central Gaza began 24 hours earlier, said Omar al-Derawi, a photographer working for the hospital.

Videos circulating online appear to show several injured people being treated on the hospital floor – a common sight in Gaza's overcrowded medical wards. Power has been cut off in large parts of the hospital as staff ration fuel supplies for the generator.

“You can't enter the hospital, there are so many people there. Women from the victims' families are crowding the corridors, crying,” he said.

Hospital records and an Associated Press reporter at the hospital recorded at least 33 deaths from the attack, including 14 children and nine women. Another attack on a house overnight killed six people, according to the records. Both attacks occurred in Nuseirat, one of several refugee camps in Gaza that date back to the war for Israel's creation in 1948, when hundreds of thousands of Palestinians fled or were expelled from their homes in the territory that later became the new state.

The footage showed bodies wrapped in blankets or plastic bags laid out in rows in the hospital's courtyard. Mohammed al-Kareem, a displaced Palestinian who has sought refuge near the hospital, said he saw people searching for their loved ones among the bodies and a woman repeatedly asked medical staff to open the sheets around the bodies to see if her son was inside.

“The situation is tragic,” he said.

Philippe Lazzarini, UNRWA's commissioner-general, said in a post on X that 6,000 people had sought shelter in the school when it was hit without warning. He said UNRWA was unable to verify claims that armed groups were in the building.

An Israeli military spokesman, Lt. Col. Peter Lerner, said the army was not aware of any civilian casualties in the attack. He said intelligence indicated that the militants had used the school compound to orchestrate some of the attacks on Oct. 7 and that at least 20 militants were currently using it as a “staging area” for attacks on Israeli soldiers. The military provided no evidence for its claims and released a photo of the school pointing to classrooms on the second and third floors, where the militants were allegedly located.

The military said it had taken measures before the attack “to reduce the risk of harm to innocent civilians … including conducting aerial surveillance and gathering additional intelligence.”

Since the beginning of the war, which has displaced most of the territory's 2.3 million Palestinians from their homes, UNRWA schools throughout the Gaza Strip have served as emergency shelters.

Last week, Israeli strikes hit near a UNRWA facility in the southern city of Rafah, reportedly targeting Hamas fighters. An inferno raged through tents housing displaced families, killing at least 45 people. The deaths sparked international outrage, and Israeli Prime Minister Benjamin Netanyahu said the fire was the result of a “tragic accident.” The military said the fire may have been caused by secondary explosions. The cause of the explosions has not yet been determined.

Israel sent troops to Rafah in early May, ostensibly on a limited basis, but those forces are now deployed in central parts of the city. Since the operation began, more than a million people have fled Rafah and spread across southern and central Gaza, moving into new tent camps or crowding into schools and homes.

Israel launched its offensive in Gaza after Hamas' October 7 attack on Israel, in which militants killed around 1,200 people and took another 250 hostage. According to the Gaza Strip's Health Ministry, which does not distinguish between fighters and civilians in its figures, at least 36,000 Palestinians were killed in the Israeli offensive.

Israel blames Hamas for the number of civilian deaths because it has stationed fighters, tunnels and rocket launchers in residential areas.

The United States has pushed for a gradual ceasefire and hostage release announced by President Joe Biden last week, while Israel says it will not end the war without destroying Hamas, while the militant group demands a permanent ceasefire and the complete withdrawal of Israeli forces.

Right-wing extremist members of Netanyahu's government have threatened to overthrow the coalition if he agrees to a ceasefire.

Israel has carried out regular air strikes on all parts of the Gaza Strip since the war began and has conducted massive ground operations in the territory's two largest cities, Gaza City and Khan Younis, leaving large parts of it in ruins.

The military launched an offensive in Bureij and several other nearby refugee camps in central Gaza for several weeks earlier this year.

Last Friday, troops withdrew from the Jabaliya camp in northern Gaza after weeks of fighting caused widespread destruction. Rescue workers have recovered the bodies of 360 people, most of them women and children, killed during the fighting.

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Samy Magdy reported from Cairo.

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