Lt. Col. Peter Lerner, an IDF spokesman, said at a news conference Thursday that 20 to 30 Hamas and Islamic Jihad fighters were operating from a compound inside the school in the Nuseirat area. The strike had previously been called off twice to limit civilian casualties, Lerner said, and he wasn’t aware of civilian deaths resulting from Thursday’s attack.

“We are confident that our activities were effective in limiting and reducing the harm to civilians in the area,” he said.

Lerner said this was the fifth time the IDF had identified Hamas and Islamic Jihad fighters using UNRWA facilities to plan attacks. A Hamas spokesman denied that the school contained a hidden Hamas command post, Reuters reported.

Lazzarini wrote on X on Thursday afternoon that the school had been sheltering 6,000 displaced people when it was hit overnight by Israeli forces “without prior warning to the displaced.”

“Attacking, targeting or using UN buildings for military purposes are a blatant disregard of International Humanitarian law,” he wrote.

The Gaza Ministry of Health put the death toll from the school attack at 40, including 14 children and nine women, and said 74 others were injured.

Israel has alleged that some of the agency’s staff took part in the October attack and that some of its facilities have been used for militant activity. An independent review concluded in April that Israel did not provide evidence for allegations that significant numbers of UNRWA workers are tied to militant groups, but added that the agency must implement more robust vetting of staff members to ensure neutrality.

Juliette Touma, UNRWA’s communications director, said in a statement to The Post that more than 170 UNRWA buildings — mostly schools that were turned into shelters — have been hit since the war began in October, killing more than 450 people.

“We call for investigations into all violations against the United Nations including attacks on our buildings,” Touma said.

Emad Abu Shawish, 37, told The Post that he was sleeping in his home near the school early Thursday when he awoke to his house shaking. When he walked outside, Shawish said he heard people screaming and calling for help. At the school, Shawish said he saw bodies on the ground, families running away and ambulances arriving.

“The scene was truly frightening,” Shawish said.

He said people were pulling dead and injured civilians out of the rubble. Baby diapers, food, blankets and mattresses were scattered across the area, Shawish said.

Among those sheltering at the school, he said, were displaced people who had just fled Israeli strikes in other parts of central Gaza.

Israel has drawn widespread international condemnation over the mounting civilian casualties in Gaza. At least 45 people were killed in a strike on a tent camp in Rafah last month, which the IDF said targeted two Hamas officials.

On Wednesday night — before Israel’s attack on the school in the Nuseirat area — al-Aqsa Hospital said in a statement through the Gaza Health Ministry that one of its two remaining generators had stopped working, threatening its ability to treat dozens of patients in critical care, including premature babies.

Here’s what else to know

An escalation in fighting between Israel and Hezbollah is adding to fears of a wider war, as Israeli officials say they will soon decide whether to launch an offensive at the border with Lebanon. The Israeli military said a reservist was killed in a Hezbollah rocket attack in northern Israel on Wednesday evening. Israeli strikes hit villages in southern Lebanon on Wednesday and overnight, sparking a fire, the Lebanese national news agency said.

The United States remains “incredibly concerned” about the situation on the Israel-Lebanon border, State Department spokesperson Matthew Miller said Wednesday, adding that Israel has said its “preference would be to resolve it diplomatically, but they were also prepared to do so militarily.” He said Washington continues “to pursue a diplomatic resolution because we don’t want to see that escalation of the conflict.”

Spain has asked to join South Africa’s case at the International Court of Justice on Israel’s operations in Gaza, Foreign Minister José Manuel Albares said Thursday. South Africa brought the case to the ICJ last year, accusing Israel of violating the Genocide Convention. Israel has denied the genocide charges. The top U.N. court last month ordered a halt to an Israeli offensive in Rafah.

Nine out of 10 children in Gaza are experiencing severe food poverty and surviving on two or fewer food groups a day, according to a UNICEF report published Thursday. “Months of hostilities in the Gaza Strip have brought the food and health systems to collapse and have had a catastrophic impact on children and families,” UNICEF said. The closure of the Rafah border crossing has restricted access to food and medical supplies, and U. S-led negotiations to reopen the crossing for aid deliveries face significant obstacles, The Post reports.

Thousands of ultranationalist Israelis marched through Jerusalem’s Old City on Wednesday for the annual Flag March, which draws settlers and other right-wing activists to mark the 1967 Israeli capture of the eastern part of the city. Some chanted anti-Arab slogans including “Death to Arabs,” the Associated Press reported. Israeli police arrested 18 people on suspicion of violent crimes, assault and threats, and disorderly conduct.

At least ​​36,586 people have been killed and 83,074 injured in Gaza since the war started, according to the Gaza Health Ministry, which does not distinguish between civilians and combatants but says the majority of the dead are women and children. Israel estimates that about 1,200 people were killed in Hamas’s Oct. 7 attack, including more than 300 soldiers, and it says 293 soldiers have been killed since the launch of its military operations in Gaza.

Ellen Francis, Miriam Berger, Lior Soroka and Louisa Loveluck contributed to this report.