JERUSALEM: Israeli jets and helicopters bombarded Gaza on Friday and Hamas responded with a barrage of rockets on two cities as both sides defied a UN call for an immediate ceasefire.

One Israeli airstrike killed two Hamas militants and another unidentified man, while another flattened a five-story building in northern Gaza, killing at least seven people, including an infant, Hamas officials said. Israeli aircraft struck more than 30 targets before dawn, and there were constant explosions after first light.

By afternoon, 22 Palestinians had been killed, pushing the death toll to 776 in the two-week-old conflict, according to Gaza health officials who said at least half of those killed were civilians. Thirteen Israelis have also been killed.