An Israeli strike on a school-turned-shelter for displaced Palestinians in Gaza that killed 18 people has drawn fierce global condemnation.

The attack flattened part of the al-Jaouni school in Nuseirat on Wednesday and killed six workers from UNRWA, the United Nations agency for Palestine refugees, which runs the school. The agency said it was the highest death toll among its team in a single incident in its history.

“Among those killed was the manager of the UNRWA shelter and other team members providing assistance to displaced people,” it said on X.

UN Secretary-General Antonio Guterres branded the strike “totally unacceptable”.

His spokesman Stephane Dujarric said women and children were among the dead.

European Union foreign policy chief Josep Borrell said he was “outraged” by the deaths and the strikes showed a “disregard of the basic principles” of international humanitarian law.

Jordan’s Ministry of Foreign Affairs spokesman Sufyan Qudah issued a statement denouncing the attack in which he said: “Israel’s continued violation of international law and international humanitarian law is a result of the absence of a strong and decisive international stance.”

The director general of the World Health Organization, Tedros Adhanom Ghebreyesus, also condemned the strike, writing on X: “The carnage in Gaza must stop.”

‘Heartbreaking scenes’

Al Jazeera’s Hani Mahmoud, reporting from Deir el-Balah, also in central Gaza, described the chaotic scenes when victims of the attack on the school were taken to hospital.

“People are bidding farewell to their relatives pronounced dead at the hospital. One person who is in critical condition was pulled from the hospital just to say goodbye to family members killed in the attack. It was a heartbreaking scene,” he said.

Mahmoud said this “is not the first time we’ve seen UN-run evacuation centres attacked”.

“These facilities are marked, their coordinates shared with the Israeli military. They are known to have turned into shelters for displaced families. But the UN’s blue and white colours on the shelters is not protecting the people inside,” he said.

Israeli military says school a ‘legitimate target’

The Israeli military on Thursday said it had conducted a “precise strike” on Hamas fighters within the school grounds.

It did not elaborate on the outcome but said “numerous steps” were taken to reduce the risk to civilians.

Without providing evidence, Israeli government spokesman David Mencer said the school was “no longer a school” and had become “a legitimate target” because Hamas used it to launch attacks.

Israeli military spokesman Lieutenant Colonel Nadav Shoshani said UNRWA had not provided the names of its killed workers “despite repeated requests” and 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”, it provided Israel each year with a list of its staff and it “called repeatedly” on Israel and Palestinian fighters “to never use civilian facilities for military or fighting purposes”.

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.