Gaza City, Gaza Strip ? The leaders of the two main Palestinian factions called for an end to fighting that killed six more people Tuesday and forced Palestinians to wonder whether their society was hurtling toward civil war.

Palestinian Authority President Mahmoud Abbas, of Fatah, and Prime Minister Ismail Haniyeh, of Hamas, signed a fresh cease-fire agreement aimed at stopping nearly a week of back-and-forth clashes.

It was not clear, however, whether the latest attempt to quell unrest would succeed, amid rising tension driven largely by Abbas’ call for early elections that could undercut Hamas’ historic victory in January’s polls.

Under the agreement, both sides are to withdraw their forces from the streets, leaving only ordinary police officers to maintain law and order. The deal, brokered by Egyptian officials, was announced separately in the West Bank and Gaza Strip.

The accord capped a long day of violent clashes that had left earlier attempts at a cease-fire in a shambles, and prompted the Education Ministry to cancel classes today.

The day began with a shootout at Gaza City’s biggest hospital that left a Hamas officer dead, and continued with an ambush on a busy downtown street that claimed two members of the Fatah-linked intelligence service and wounded seven bystanders, including five children.

Two other Fatah members were abducted and killed, and their bodies left on a street near the hospital.