Palestinians living along Gaza's northern and eastern borders are fleeing intense Israeli bombardment.
Families toting supplies sought refuge on Friday in temporary shelters in central Gaza City as Israeli artillery pounded northern Gaza in an attempt to destroy a vast network of militant tunnels, the military said, bringing the front lines closer to dense civilian areas.
Fleeing families arrived in pickup trucks, on donkeys and by foot at schools run by the United Nations, hauling pillows and pans, blankets and bread.
Men lugged large plastic bags and women carried infants on their shoulders, cramming into classrooms.
Israel has massed troops along the border and called up 9,000 reservists following days of fighting with the Islamic militant group Hamas, which controls Gaza.
Palestinians militants have fired some 1,800 rockets and the military has launched more than 600 airstrikes, toppling at least three apartment blocks.
The Gaza Health Ministry says the death toll has risen to 119 killed, including 31 children and 19 women, with 830 wounded.
Seven people including one child are known dead in Israel.