John Ging, the senior U.N. official in Gaza, said 30 Palestinians died and 50 were injured when three artillery shells sprayed shrapnel through the Al Fakhoura School in the Jabaliya refugee camp. Palestinian doctors put the death toll at 37, including women and children.
Hours before, the United Nations said another of its schools in the Shati refugee camp, also in northern Gaza, which had been closed because of the bloodshed, was hit by an Israeli missile early Tuesday, killing three Palestinian cousins who had taken shelter inside.
Hundreds of Gazans have been relying on U.N. buildings as havens amid the fighting between Israeli forces and Hamas militants that began 11 days ago when the Israelis initiated an air barrage designed to halt rocket attacks by Hamas on southern Israel.
The Israeli army said the school in Jabaliya was attacked after militants fired mortars from the campus. An army statement said Hamas "terror operatives" Imad Abu Askhar and Hassan Abu Askhar were among the dead.
"We face a very delicate situation where Hamas is using the citizens of Gaza as a protective vest," Israel Defense Forces spokesman Brig. Gen. Avi Benayahu said.
Fawzi Barhoum, a spokesman for the Islamic militant group, denied that his organization was staging attacks from the school and accused Israel of carrying out "an open war on innocent civilians."
Israeli warships battered the coast as troops and tanks, after intense fighting around Gaza City, pushed south to Khan Yunis, where skirmishes continued throughout the day.
Thousands of Gazan families have abandoned their homes, either to flee the front lines of the conflict or because of their proximity to police stations or security forces installations. Those who don't seek safety in public shelters, such as the U.N.-run schools, often shuffle between the homes of relatives.
But even many purely civilian neighborhoods aren't safe because Gaza militants often fire rockets from such areas and Israel continues to bomb the homes of Hamas commanders and buildings and mosques it believes are used as weapons storehouses. As a result, almost every neighborhood in Gaza is littered with sites that Israel considers legitimate military targets.
The situation is perilous even for those seeking maternity care in Gaza's overloaded hospitals. Pregnant women face the decision of whether to deliver at home or risk trying to reach a medical facility, where critically injured patients take priority. Gaza City's main Shifa Hospital emptied its maternity ward on the first day of the Israeli air assault.
