Israeli strikes in the northern and central Gaza Strip on Wednesday killed at least 31 Palestinians, most of them in Beit Lahiya town in the north of the enclave, medics said.
Health officials said an Israeli air strike on a house in Beit Lahiya killed at least 22 people, including women and children. Relatives listed the names of the dead on social media.
The Palestinian news agency WAFA said at least 30 people were living in the multi-storey building before it was struck, adding that several members of the family remained missing as rescue operations continued through morning hours.
The Israeli military said it was checking the report.
Earlier on Wednesday, at least seven Palestinians were killed and several others wounded in an Israeli air strike on a house in the Nuseirat camp in the central part of the Gaza Strip, medics told Reuters.