Israeli strikes on two schools in Gaza City killed 25 Palestinians, most of them women and children, according to Gaza Civil Defense.
The Israeli military confirmed the strikes, albeit saying militants were using the sites.
"The schools were used by Hamas' Al-Furqan Battalion as a hiding place for its terrorist operatives and as command centers," the military said in a statement, a claim that could not be indepently verified.
Gaza officials say Israeli strike kills 5 at hospital
Five people died when an Israeli airstrike hit a hospital compound in Gaza, health officials said on Sunday.
A further 18 people were wounded in the incident, Palestinian medical authorities said.
The Israeli military said it had targeted a militant who "conducted terror activities." It also said it identified secondary explosions, "indicating the presence of weaponry in the area."
In June, the Office of the United Nations High Commissioner for Human Rights accused Israel of "systematic attacks on hospitals and other medical facilities in violation of the laws of war."
The strike on the Al-Aqsa hospital compound was one of several across the Gaza Strip on Sunday. The Israeli army said it hit "approximately 50 terror targets" in the past 24 hours.
The hospital compound is in the Deir Al-Balah area, which is crowded with thousands of people displaced by fighting in other parts of the enclave.
Meanwhile, the Hamas-run Health Ministry said on Sunday that 33 people had died in Gaza in the past 24 hours of fighting, with its given total since October 7 now approaching 40,000.