Rival Palestinian factions Fatah and Hamas have agreed to form a unity government led by current President Mahmoud Abbas.

A Palestinian official said Monday the agreement was reached at a meeting in Qatar.

The official said the deal calls for Mr. Abbas to assume the role of prime minister, replacing Western-backed Salam Fayyad.

It was not immediately clear when the new government will be formed.

Hamas and Fatah first agreed to form a unity government in May of last year. Hamas rules the Gaza Strip, while Fatah heads the more moderate Palestinian Authority in the West Bank.

Hamas, an Islamic militant group regarded by the West as a terrorist organization, won a landslide victory in Palestinian elections in 2006. It took over Gaza from forces loyal to Mr. Abbas's Fatah movement in 2007, after months of factional unrest.