By KARIN LAUB and YOUSUR ALHLOU
BEIT LAHIYA, Gaza Strip (AP) -- Sobbing and shaking, Ismail Abu Musallam leaned against the wall of a hospital Friday, waiting for three of his children to be prepared for burial. They were killed as they slept when an Israeli tank shell hit their home, burying 11-year-old Ahmed, 14-year-old Walaa and 16-year-old Mohammed under debris in their beds.
His personal tragedy is not unique: the U.N. says minors make up one-fifth of the 299 Palestinians killed in 11 days of intense Israeli bombardment of the densely populated Gaza Strip, where half the 1.7 million people are under age 18.
The Israeli military says it's doing its utmost to spare civilians by urging residents to leave areas that are about to be shelled or bombed as Hamas targets. It accuses the Islamic militants of using civilians as human shields by firing rockets from civilian areas.
But even if urged to evacuate, most Gazans have no safe place to go, rights activists say.
"If you are going to attack civilian structures in densely populated areas, of course you are going to see children killed," said Bill Van Esveld, a researcher for New York-based Human Rights Watch.
Seventy-one of those killed since fighting began on July 8 were under 18, according to an Associated Press count based on information provided by Palestinian health official Ashraf al-Kidra. Forty-eight of the victims were under the age of 13.
Many of the children were killed in their own homes.
Early Friday, a 5-month-old baby boy was hit by shrapnel from a missile strike near his family compound in the southern town of Rafah. A day earlier, two brothers and a cousin were killed by shrapnel while feeding pigeons on the roof of their home.
One deadly incident drew particular outrage. Four cousins, aged 9 to 11, had been playing on the beach near Gaza City's harbor on Wednesday when a missile fired from an Israeli gunboat hit a nearby shack. The boys fled, but were killed in a second missile strike.
The images of small, bloodied bodies lying face down in the sand triggered harsh international criticism, including from U.N. chief Ban Ki-moon who said Israel must "do far more to stop civilian casualties."
The Israeli military said Hamas operatives were the target, and promised to investigate.
Lt. Col. Peter Lerner, a military spokesman, said Friday that "Israel's efforts to try to minimize civilian casualties are unprecedented in the Western world," referring to its system of delivering evacuation warnings through text messages, automated calls and leaflets dropped from planes.
He said more than a dozen attacks were aborted when civilians were spotted in the area.
"Unfortunately, the Hamas infrastructure placed itself intentionally between the civilian population," he said.
In recent days, Israel repeatedly urged people living near the border with Israel to leave their homes. As it later turned out, this was in part in preparation for the ground offensive Israel launched late Thursday, sending in thousands of troops.
Border areas, including the northern town of Beit Lahiya, came under heavy shelling attack. Across Gaza, the heavy thuds of tank fire could be heard through the night from Thursday to Friday, often just seconds apart.
Like many in Beit Lahiya, Abu Musallam decided to remain in his apartment with his wife and seven children even as their neighborhood came under intense artillery fire.
Eventually, the children went to sleep. The oldest, Mohammed, was in one room, and little Ahmed and his sister Walaa in another, the 40-year-old carpenter said.
At some point in the night, a tank shell hit the apartment, burying the three children under debris. Abu Musallam said he had to call for help to pull them from the wreckage. They were taken to a local hospital where each was wrapped in a white shroud and placed in the morgue's refrigerator. Ahmed's face was blackened from soot.
Surrounded at the hospital by a throng of relatives and his 15-year-old son Omar, the bereaved father fought back tears Friday, as he spoke about his children. He said Mohammed had worked with him in his carpentry workshop and that Ahmed was a kind boy.
The sadness then turned to anger.
"We are with the resistance," he said, referring to Hamas militants who helped provoke the Israeli assault by firing more than 1,500 rockets at Israel in close to two weeks. "Three children died and I can offer another three just to give Palestine its freedom."
Nearby, young boys hanging outside the hospital tried to sound street-wise and unfazed by the death around them.
Fourteen-year-old Yousef Aliyan said he had walked from his nearby home to watch dead and wounded being brought to the hospital. He's not afraid, he said.
"This is not the first time we came under shelling attack," he said. "I'm used to it."
Alhlou reported from Jerusalem.