Tensions between Abbas and Hamas have been increasing since the Islamic militant group, which won a January parliamentary election, took power in March.

Abbas, elected separately last year, still wields considerable authority and Fatah and Hamas are battling over control of the security forces. Factional fighting in Gaza's streets has raised the specter of civil war.

The unsuccessful negotiations between Abbas and Hamas over the prisoners' document also have exposed divisions between Hamas' local officials and its Syria-based leadership, which has held sway.

Meanwhile, new violence erupted between gunmen loyal to the president and Hamas' militia before Abbas' announcement.

Gunmen shot and killed a 39-year-old Palestinian security officer in a botched kidnapping attempt, Palestinian Preventive Security officials said. The force, loyal to Abbas, accused Hamas of the killing and vowed to impose justice.

During the funeral procession, a gunbattle erupted between gunmen from Hamas and the Preventive Security force. The car of Gaza's top pro-Abbas general was caught in the crossfire, and he was rushed out of the area.

Four people were wounded, including one seriously, hospital officials said. Hamas gunmen took up positions in the area, leading to a tense standoff.