The United Nations has demanded an investigation into strikes near a United Nations-run school in Gaza that killed 42 civilians.
The attack, from Israeli tanks or mortars, happened at the al-Fakhora school in Jabaliya refugee camp, causing carnage inside and outside the building, where hundreds of Palestinians had sought refuge from fighting between Israeli soldiers and Hamas militants.
The school was clearly marked with a UN flag.
Two other Israeli attacks on UN schools in Gaza left five dead, pushing the Palestinian toll to more than 660. The attacks have highlighted the growing concern about the humanitarian situation as fighting enters its 11th day.
A UN official in Gaza said the al-Fakhora school's location had been reported to Israeli authorities, and 350 people were sheltering there.
The Israeli army said it had information the school was booby-trapped, and that Hamas operatives were among the dead.
Since the attack on the school, the Israeli government said it has agreed to open a humanitarian corridor into the Gaza Strip to ship vital supplies to some of the 1.5 million Palestinians living there.
Under the plan, Israel would suspend attacks in specified parts of Gaza to allow people to stock up on essential goods.
More than 2,700 Palestinians have been wounded since the campaign began on 27 December in retaliation for rocket attacks by Hamas on southern towns in Israel.
Palestinian health ministry officials say 595 people, including 195 children, have been killed since the attacks began.