A girl with tears in her eyes is having a rest at a UN school in Gaza on Nov. 21, 2012.Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)

Israeli fighters are hovering above Palestine children hiding at a UN school in Gaza on Nov. 21, 2012. Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)

Palestine residents are registering with staffs of UN at a UN school in Gaza on Nov. 21, 2012. Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)

A Palestine girl is comforting her little sister at a UN school in Gaza on Nov. 21, 2012. Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)

A Palestine girl from northern Gaza sits in front of the desk at a UN school in Gaza on Nov. 21, 2012. Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)

A Palestine youth is helping UN staffs to prepare mattress for Palestine refugees at a UN school in Gaza on Nov. 21, 2012. Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)

A Palestine resident is checking luggage at a UN school in Gaza on Nov. 21, 2012. Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)

A Palestine resident shows a warning leaflet from Israeli airplanes at a UN school in Gaza on Nov. 21, 2012. Israeli air force on Tuesday attacked the northern and northeastern areas of Gaza Strip where they dispatched leaflets in arabic to local residents by airplane, telling them to leave their home and flee for their lives.(Xinhua/Chen Xu)