JEBALIYA REFUGEE CAMP, Gaza Strip (AP) -- Israeli tank shells slammed into a crowded United Nations school sheltering Gaza war refugees today, killing 15 Palestinians and wounding 90 after tearing through two classroom walls, a health official and a spokesman for a UN aid agency said.
The Israeli military had no immediate comment.
The strike in the Jebaliya refugee camp came amid Israel's heaviest air and artillery assault in more than three weeks of Israel-Hamas fighting. Tuesday marked the deadliest day so far, with 128 Palestinians killed, according to a Gaza health official.
The overall Palestinian death toll rose to at least 1,258, with more than 7,100 wounded, said the health official, Ashraf al-Kidra. Israel has lost 53 soldiers and three civilians.
Today, the military said it hit 75 sites, including five mosques it claimed were being used by militants. At the same time, intense tank shelling was reported in some areas, including in Jebaliya.
Tank shells hit a UN school in the camp early today, said Adnan Abu Hasna, a spokesman for the UN Relief and Works Agency.
The agency is sheltering more than 200,000 people displaced by the fighting at dozens of UN schools in Gaza.
Starting at around 4:30 a.m., several shells hit the compound of the Abu Hussein school, a few minutes apart, said the principal, Fayez Abu Dayeh. He said shells hit two classrooms and a bathroom.
In one of the classrooms, the front wall was blown out, leaving debris and bloodied clothing. Another strike tore a large round hole into the ceiling of a second floor class-room.
About two hours after the strike, hundreds of people still crowded the courtyard, some dazed, others wailing.
Aishe Abu Darabeh, 56, sat on the ground with her relatives, just a few meters from the destroyed classroom.
"Where will we go?" she asked. "Where will we go next? We fled and they (the Israelis) are following us."
Four of the dead were killed just outside the school compound, two in their home and two who were struck in the street after returning from pre-dawn prayers, their relatives said.
The bodies of two members of the al-Najar family, 56-year-old Shaher and his 41-year-old brother, Bassem, were laid out in one of the rooms of their small home, surrounded by wailing relatives.
Outside the gate, another relative held on to his crying son, hugging him tight and saying: "I'm here, I'm not going anywhere."
Al-Kidra, the health official, said at least 15 people were killed and about 90 wounded in the strike on the school.
Abu Hasna, the UN agency spokesman, said the international community must step in.
"It's the responsibility of the world to tell us what we shall do with more than 200,000 people who are inside our schools, thinking that the UN flag will protect them," he said. "This incident today proves that no place is safe in Gaza."
The deadly strike came as Israel intensified its air and artillery assault on what it says are Hamas targets in Gaza.
Israel has vowed to stop the Hamas rocket and mortar fire that has reached increasingly deeper into its territory and to destroy a sophisticated network of Hamas military tunnels used for attacks in Israel.
For its part, Hamas has so far rejected cease-fire efforts unless its demands are met, including a lifting of a punishing blockade.
The military said that since fighting began July 8, Israeli forces have hit 4,100 targets in Gaza, about one-third connected to the militants' ability to launch rockets at Israel.
An army statement said that since Tuesday morning, troops have demolished three more tunnels leading from Gaza to Israel. Hamas has used such tunnels to sneak into Israel to carry out attacks.
The army said 32 tunnels have so far been located but did not say how many remain.
Enav reported from Jerusalem. Associated Press writer Ibrahim Barzak in Gaza City contributed to this report.