The bloodshed has renewed fears of a full-scale civil war in Gaza and has left the fragile government uniting president Mahmud Abbas's Fatah party and the Islamist Hamas teetering just two months after it assumed office.

In a move that could further spiral the internecine violence that has killed 38 people in four days, an Israeli aircraft bombed a Hamas training camp in Gaza, killing four and wounding several others, medics and witnesses said.

Hamas said the missiles struck one of its military buildings in the town. The Israeli army confirmed its aircraft fired on southern Gaza, but did not give details.

Palestinian officials said the strike killed at least four people and injured 14 others, including one critically. Palestinian rescue officials said several people were buried under rubble after the strike.

Gaza's streets remained largely deserted except for prowling armed men as civilians cowered indoors, stores were shuttered and schools were closed.

As international calls for a halt to the violence increased, Abbas and Hamas's exiled political supremo Khaled Meshaal agreed to halt the bloodshed.

In a telephone call, Abbas and Meshaal "agreed on the necessity to put an end to the bloody events between Hamas and Fatah in Gaza," information minister Mustafa Barghuti told AFP.

Deputy prime minister Azzam al-Ahmad told AFP that Abbas could declare a state of emergency.

"We have requested with other ministers present in Ramallah a meeting with the president to take measures to put an end to the current crisis," he said.

Abbas was due to discuss the spiralling violence at a meeting of the Palestine Liberation Organisation in Ramallah in the occupied West Bank later in the day.

Wednesday's bout of violence, the deadliest since the latest fighting began on Sunday, erupted just hours after the rival factions announced for a third time that they had agreed a truce.

Five Fatah men were killed as a result of a brazen attack by Hamas on the Gaza home of the pro-Fatah Palestinian security supremo, Rashid Abu Shbak.