The strikes came after Hamas on Monday released an Israeli American hostage, a gesture that some thought could lay the groundwork for a ceasefire.

Hospitals say 29 children and 15 women were among the dead after the northern Jabalia area were hit overnight.

Medics said two strikes targeted the Karama School in Tuffah, a suburb of Gaza City, killing 15. Later in the day, an Israeli strike near a restaurant and market in the city killed at least 33 people, including women and children, medics said.