An Israeli air attack on a school sheltering thousands of displaced Palestinians in northern Gaza has killed at least 15 people.

The Israeli military confirmed it struck the school in the Jabalia refugee camp, claiming it was targeting Hamas fighters.

The bombing on Thursday brought the number of people killed in the Gaza Strip in the last 24 hours to 36.

Footage from the Hafsa al-Faluja School showed rescue workers rushing casualties out of the compound amid widespread debris and crowds of people. One video showed men wrapping a mangled, severed torso in a plastic sheet and putting body parts into a cooler.

Israeli forces have repeatedly struck schools, alleging that Hamas uses them as “command centres” to plan attacks. The Palestinian group has denied the charges.

Many school buildings have been repurposed to shelter displaced families across the besieged enclave where the majority of its 2.3 million people have been repeatedly uprooted by the war.

In the southern city of Khan Younis, the authorities buried the bodies of 88 Palestinians that Israel returned to Gaza in a mass grave.

The Health Ministry denounced what it called the “inhumane and immoral” way Israel had treated the bodies, saying they were sent back piled in a truck with no information to identify them.

Israel’s war on Gaza has killed at least 41,534 Palestinians and wounded 96,092, according to the latest figures released on Thursday by the Health Ministry. More than half of the dead have been women and children, including about 1,300 babies and toddlers under the age of two.