Palestinians run for cover as warning airstrikes are fired at a building in Gaza City, above.
Civilians in densely-populated Gaza have no place to hide from Israel's military offensive and children are paying the heaviest price, the United Nations said on Tuesday. "There is literally no safe place for civilians," Jens Laerke, spokesman of the U.N. Office for Humanitarian Assistance, told a news briefing in Geneva. More than 500 people have been killed in the coastal enclave which has an estimated 4,500 people per square kilometer, Laerke said.
