JEBALIYA REFUGEE CAMP, Gaza Strip (AP) Israeli tank shells slammed into a crowded U.N. school Wednesday sheltering Gazans displaced by fighting, killing 15 and wounding 90 after tearing through the walls of two classrooms, a spokesman for a U.N. aid agency and a health official said.
Later in the day, Gaza health officials say 15 people were killed and more than 150 wounded by an Israeli airstrike in a crowded shopping area.
The Israeli military had no immediate comment.
Gaza health ministry official Ashraf al-Kidra says the area was busy Wednesday because residents thought a cease-fire was in place. The Palestinian Red Crescent confirmed the death toll.
Israel had earlier announced a "humanitarian window" in certain parts of the territory. It said it would not halt fire in other areas, including in Shijaiyah, where the strike took place.
The strike at the U.N. school in the Jebaliya refugee camp came amid Israel's heaviest air and artillery assault in more than three weeks of Israel-Hamas fighting. On Wednesday, Israeli aircraft struck dozens of Gaza sites, including five mosques it said were being used by militants, while several other areas came under tank fire.
The Israeli military said it is looking into the incident. Its campaign escalated on Tuesday, with airstrikes destroying key symbols of Hamas power, including the home of the top Hamas leader. Gaza's only power plant was shut down after shells set its fuel tank on fire.
After the incident the Israeli military said it declared a cease-fire in some areas of the Gaza Strip for humanitarian reasons.
A Hamas spokesman says the four-hour cease-fire declared by Israel doesn't have any "value," because it excludes border areas from which Hamas wants to evacuate the wounded.
Israel's military says its forces are still working to demolish tunnels in some areas of the Strip. It says at least two rockets were fired at Israel after its declaration to partially hold fire.
In Jebaliya, tank shells hit the U.N. school before dawn, said Adnan Abu Hasna, a spokesman for the U.N. Relief and Works Agency. The agency is sheltering more than 200,000 people displaced by the fighting at dozens of U.N. schools across the coastal strip.
Assad Sabah said he and his five children were huddling under desks in one of the classrooms because of the constant sound of tank fire throughout the night.
"We were scared to death," he said. "After 4:30 a.m., tanks started firing more. Three explosions shook the school."
"One classroom collapsed over the head of the people who were inside," he said.
In one classroom, 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 classroom. The wall of the lavatories was also damaged.
About two hours after the strike, hundreds of people still crowded the school courtyard, some dazed, others wailing.
Aishe Abu Darabeh, 56, sat on the ground with her relatives, just a few meters (yards) away.
"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 nearby and two 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."
Abu Hasna, the U.N. 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 U.N. flag will protect them," he said. "This incident today proves that no place is safe in Gaza."
Ashraf al-Kidra, a Gaza health official, said at least 15 people were killed and about 90 wounded in the school strike.
In all, 42 Palestinians were killed by airstrikes and tank shelling in different areas of Gaza on Wednesday, al-Kidra said.
The total number of Palestinians killed since the start of fighting July 8 rose to 1,269, al-Kidra said. In addition, more than 7,100 Palestinians have been wounded.
Israel has lost 53 soldiers and three civilians.
Israel has said its Gaza operation is meant to stop 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.
Gaza militants have fired more than 2,600 rockets toward Israel over the past three weeks, according to the Israeli army.
The Israeli military has said it is hitting targets linked to militants, such as rocket launching sites, weapon depots and Hamas military tunnels. Over the past 23 days, Israeli forces have hit 4,100 targets in Gaza, about one-third connected to the militants' ability to launch rockets at Israel, a statement said.
The military has not provided details on strikes in which multiple members of one family were killed. There have been several dozen such strikes, according to the Palestinian human rights group Al- Mezan.
The military says Hamas militants often launch rockets from crowded residential areas, thus endangering nearby civilians. The army says it has also given civilians a chance to leave dangerous areas by sending warnings in phone calls and leaflets.
On Wednesday, aircraft dropped leaflets over Gaza City's Rimal neighborhood. The leaflets urged residents to stay away from Hamas militants and to report possible rocket launches. The leaflet gave a contact phone number and email.
"The Israeli Defense Forces are going into a new phase in the coming operation and does not want to harm civilians," the leaflet said. "The army is warning residents in the areas where the operation will take place that for your safety, you have to keep away from terrorists and the locations from which they operate."
Separately, Israeli troops in Gaza's border areas are searching for Hamas military tunnels used for carrying out attacks in Israel. Israeli leaders have said troops would not leave until all the tunnels have been demolished.
The army said 32 tunnels have so far been located but did not say how many remain. Since Tuesday morning, troops have demolished three more tunnels, a statement said.