The volatile mix of Israeli strikes and Palestinian infighting plunged Gaza deeper into chaos.

Five Palestinians were killed in a single airstrike by Israel, which said it was responding to Hamas rocket attacks on southern Israel a campaign that showed no sign of subsiding Friday. Hamas fired three rockets at the town of Sderot, where three people were injured by shrapnel and several others were treated for shock.

The sound of gunfire and explosions from fighting between Hamas and Fatah rang out for the sixth straight day in Gaza. Outside the Islamic University a Hamas stronghold one person was wounded from the exchange of fire but it was not immediately known from which side.

Members of Palestinian President Mahmoud Abbas' presidential guard and other Fatah loyalists were advancing on Hamas fighters from different directions and the house of the university's dean was attacked by rocket propelled grenades, according to Hamas.

However, presidential guard spokesman Ali al-Kaisi denied his group was involved in any attack on the university.

The university's president, Kamelen Shaath, appealed for an immediate halt to the violence.

"Universities must be outside the circle of violence and I appeal to the president and all the wise people on both sides to try and spare the university the agony of this fight," he said.

In six days of mayhem, 46 Palestinians have died in the infighting and another 17 were killed in Israeli strikes.

The fighting between Hamas and Fatah has all-but destroyed a two-month-old power sharing deal between them, and brought them close to all-out civil war. The Israeli strikes have introduced a new layer of violence and uncertainty though a senior army official, speaking on condition of anonymity because no official decision has been made, said Israel had no immediate plans for a major ground offensive to halt rocket fire.

Israeli aircraft fired missiles east of Gaza City on Friday, killing five Palestinians, at least three of them Hamas militants, and wounding six people, Hamas and local doctors said. The military said the target was a Hamas headquarters building. Two other strikes followed but there was no word of any casualties, Palestinian doctors said. The army said it struck at a squad that fired rockets into Israel.

The Palestinian street battles were down from their height two days ago, but the latest cease-fire worked out between the sides was not holding. Gunfire could be heard in many areas, and gunmen who had promised to withdraw from the streets were still manning roadblocks and taking up positions on rooftops.