A frame from a video capturing Palestinian refugees killed in an Israeli airstrike on a school in Jabalia camp in Gaza, 18 november, 2023
"At least 50 people" were killed in an Israeli strike at dawn on the UN-run Al-Fakhura school in the camp," the official told AFP.
TV channels and social media videos showed bodies of children covered in blood and dust on the floor of a building, where mattresses and blankets had been wedged under school tables.
A separate strike on another building in the camp on Saturday killed 32 people from the same family, 19 of them children, the health ministry official said.
The ministry released a list of 32 members of the Abu Habal family it said had died.
Jabalia is the biggest refugee camp in Gaza, where some 1.6 million have been displaced by more than six weeks of the Israeli war on Gaza.
The UN agency for Palestinian refugees (UNRWA) was unable to offer an immediate reaction, but the UN agency Media Advisor Adnan Abu Hasna told Al Jazeera: "We inform the Israeli side daily of the locations of our schools and centers for the displaced."
At the start of November, the Gaza government said more than 200 people had been killed and hundreds more wounded in Israeli bombardments on the Jabalia camp over three consecutive days.
The Israeli army's relentless air and ground campaign has killed anout 12,000 people, 5,000 children were among the dead alongside 3,300 women, with 30,000 more people wounded.