Palestinian gunmen march in Deir Al Balah in the central Gaza Strip during the funeral of eight security force officers loyal to the Fatah movement who were killed during an attack by Hamas militants. Hamas gunmen on Tuesday ambushed the rival Fatah forces near a key crossing along the Israeli border, killing the eight officers in the deadliest battle yet in three days of factional fighting. The incident briefly drew Israeli gunfire, threatening to drag Israel into the conflict.

Gaza City, Gaza Strip ? Eight bodies sprawled face down in a cornfield, next to an overturned jeep, signaled a new phase in Gaza’s increasingly brutal civil strife.

The eight, members of a force loyal to Palestinian President Mahmoud Abbas’ moderate Fatah movement, had rushed to back up embattled comrades Tuesday when their jeep was ambushed by the Islamic militant Hamas group, veered off the road and overturned.

Hamas militants then riddled the vehicle with bullets, killing the trapped policemen execution-style, said a witness, who works at a nearby factory. “It was unbelievable. May God help us,” said the man, who gave only his first name, Jamil, out of fear for his safety.

The most ruthless round of factional fighting yet has pushed the fragile Palestinian unity government closer to collapse. Gunmen in black ski masks took up positions in the streets and terrified residents huddled in their homes. Israel, too, was briefly drawn into the battle.

An Egyptian mediator said a truce was reached late Tuesday – the third in as many nights. The others have collapsed within hours.

“I don’t know when it’s going to end and what the future will bring,” said Salman Abu Arafeh, 42, a Gaza City interior decorator who was pinned down by gunfire in the hallway of his apartment for hours, along with his wife and two children. A total of 15 people were killed Tuesday.

In the West Bank, Palestinian President Mahmoud Abbas called for the immediate implementation of a security plan that would put all rival forces under one command. However, his call is unlikely to be heeded: the fighting made it clear the Hamas-Fatah power struggle was never really resolved, despite the formation of the unity government in March.

Gaza’s turmoil further weakened hopes for a resumption of Israeli-Palestinian peace talks, despite a new push by the Arab world to bring the sides to the table, based on an offer of Arab recognition of Israel in exchange for an Israeli withdrawal from all lands it occupied in the 1967 Middle East War.