Live updates: Follow the latest on Israel-Gaza
Israeli air strikes on Gaza city killed at least 14 people on Wednesday night and into Thursday morning, Palestinian media reported, as the army continued to escalate attacks on central parts of the enclave.
Four people, including a child, were killed in a strike on a home in Al Tuffah neighbourhood, Wafa news agency reported, while five people, including two children, were killed in an attack on a house in Al Zeitoun district. Two people were later killed in a dawn air strike on Al Zeitoun.
Another air strike killed three in Al Nasr neighbourhood, Wafa reported.
The army has intensified attacks on Gaza city in recent days, with heavy shelling and regular air strikes reported across the city and its outskirts. Repeated attacks since the war began have forced many of the city's residents to move elsewhere.
A dawn air strike killed also three people in Jabalia refugee camp, while extensive attacks were also reported on the Nuseirat and Bureij camps.
The death toll of an earlier strike on Al Jawni school in Nuseirat refugee camp rose to 18, including six employees of the UN's agency for Palestinian refugees (UNRWA) – the organisation's biggest loss in a single attack since the war began. At least 18 were wounded, Gaza's civil defence said.
UN Secretary General Antonio Guterres criticised Israel after the attack, saying what is happening in Gaza is “unacceptable”.
About 12,000 displaced people had sought shelter in the school at the time of the attack, Mr Guterres said.
“These dramatic violations of international humanitarian law need to stop now,” he wrote on social media.
The UNRWA said it was the fifth attack on the school since the war began. The agency's director, Philippe Lazzarini, condemned the “endless and senseless killing”.
“The longer impunity prevails, the more international humanitarian law and the Geneva Conventions will become irrelevant,” Mr Lazzarini wrote on social media, calling for an immediate ceasefire.
Survivors of the strike scrambled to retrieve bodies and belongings from the rubble. “I can hardly stand up,” one man told AFP.
“We've been going through hell for 340 days now, what we've seen over these days, we haven't even seen it in Hollywood movies, now we're seeing it in Gaza.”
Sixteen people were killed in a previous strike on the school in July.
Israel's permanent representative to the UN Danny Danon criticised Mr Guterres for his remarks on the latest strike, accusing the Secretary General of “distorting reality”.
The army said it carried out a “precision strike” on the school, which it said was being used as a Hamas command centre. The militant group has previously denied such accusations.
Schools have been regularly hit by Israeli bombardment, with dozens killed at a time.
More than 100 people were killed in Gaza city last month in an attack on a school where thousands of displaced people were sleeping and praying.
About 41,100 people have been killed and 95,000 wounded across Gaza since the war began, according to the enclave's Health Ministry.
The war broke out on October 7, when Hamas killed about 1,200 people and abducted about 240 during attacks on southern Israel.