A Hamas health official said more than 80 people were killed on Saturday in twin strikes on a northern Gaza refugee camp, including a UN school used as a shelter for people displaced by the Israel-Hamas war.

Social media videos -- which AFP was unable to immediately verify -- showed bodies covered in blood and dust on the floor of a building, where mattresses had been wedged under school tables in Jabalia, the Palestinian territory's biggest refugee camp.

Israel has vowed to destroy Hamas in response to the October 7 attacks which Israeli officials say killed about 1,200 people, most of them civilians in southern Israel, and saw about 240 people taken hostage.

The army's relentless air and ground campaign has since killed 12,000 people, including 5,000 children, according to the Hamas government which has ruled Gaza since 2007.

"At least 50 people" were killed in an Israeli strike at dawn on the UN-run Al-Fakhura school in the camp, which had been converted into a shelter for displaced Palestinians, an official at Gaza's Hamas-controlled health ministry told AFP.

According to UN figures, some 1.6 million people have been displaced inside Gaza by six weeks of fighting.

A separate strike Saturday on another building in Jabalia camp killed 32 people from the same family, 19 of them children, the official said. The ministry released a list of 32 members of the Abu Habal family it said had died.

The Israeli army did not immediately respond to requests for comment on the two strikes. (AFP)