Israel faced international condemnation Thursday after a strike killed 18 people at a school-turned-shelter for displaced Palestinians in war-torn Gaza.
The attack flattened part of the UN-run Al-Jawni school in Nuseirat on Wednesday, leaving only a charred heap of rebar and concrete.
"For the fifth time, Israeli forces bombed the UNRWA-run Al-Jawni School, killing 18 citizens," Gaza civil defence spokesperson Mahmud Bassal wrote on Telegram, referring to the UN agency for Palestinian refugees.
UNRWA later said six of its staff had been killed in two Israeli strikes on the school and its surroundings, calling it the highest death toll among its team in a single incident.
"Among those killed was the manager of the UNRWA shelter and other team members providing assistance to displaced people," it said on X. "Schools and other civilian infrastructure must be protected at all times, they are not a target."
UN chief Antonio Guterres branded the strike "totally unacceptable". His spokesman Stephane Dujarric said that women and children were also among the 18 dead.
EU foreign policy chief Josep Borrell said he was "outraged" by the deaths and that the strikes showed a "disregard of the basic principles" of international humanitarian law.
US Secretary of State Antony Blinken said: "We need to see humanitarian sites protected, and that's something that we continue to raise with Israel".
Israeli military spokesman Lieutenant Colonel Nadav Shoshani said UNRWA had not provided the names of its killed workers, "despite repeated requests".
He said a military inquiry found that "a significant number of the names (of the dead) that have appeared in the media and on social networks are Hamas terrorist operatives".
In response, UNRWA spokeswoman Juliette Touma said the agency was "not aware of any such requests", that it provided Israel each year with a list of its staff and that it "called repeatedly" on Israel and Palestinian militants "to never use civilian facilities for military or fighting purposes".
She said the agency was "not in a position to determine" if the school had been used by Hamas for military purposes, but UNRWA had "repeatedly called for independent investigations" into "these very serious claims".
Israeli government spokesman David Mencer said the school was "no longer a school" and had become "a legitimate target" because it was used by Hamas to launch attacks.
Survivors of the strike scrambled to recover bodies and belongings from the rubble, saying they had to step over "shredded limbs".
"I can hardly stand up," a man holding a plastic bag of human remains told AFP.
"We've been going through hell for 340 days now," he said.
UNRWA head Philippe Lazzarini said after the school strike that at least 220 members of the agency's staff had been killed in the war.
"Humanitarian staff, premises & operations have been blatantly & unabatedly disregarded since the beginning of the war", he said on X.
Across Gaza, many school buildings have been repurposed to shelter displaced families, with the vast majority of the territory's 2.4 million people repeatedly uprooted by the war.
A UN report published Thursday found that Gaza's economy was now less than one-sixth of the size it had been in 2022.
"It will take decades to bring Gaza back to where it was in October 2023",
UN Trade and Development economist Mutasim Elagraa warned: "It will take decades to bring Gaza back to where it was in October 2023."