>GAZA CITY, Gaza Strip (AP) – A rally of more than 250,000 Fatah supporters ended in mayhem Monday, with Hamas police opening fire and protesters hurling rocks or running for cover. Seven civilians were killed and dozens were wounded in the violence between Palestinian factions.

The demonstration in a Gaza City square, marking the Nov. 11, 2004 death of iconic Palestinian leader Yasser Arafat, posed the strongest challenge to Hamas rule in Gaza since the Islamic militant group seized the impoverished territory by force in June. The images of Hamas policemen facing off against large groups of rock-throwers challenged Hamas’ claim that it has established tight control.

Fatah’s unexpected show of strength was also its most persuasive argument that its leader, moderate Palestinian President Mahmoud Abbas, has a mandate to renew peacemaking with Israel at a U.S.-hosted Mideast conference in Maryland later this month.

The march started out peacefully after Palestinians in buses, on foot and on donkey carts streamed into a large sandy lot by the Mediterranean. Waving yellow Fatah flags, the crowd cheered and whistled as the movement’s remaining leaders in Gaza – most had fled to the West Bank in June – delivered hopeful speeches about a comeback.

But the rally quickly descended into chaos and bursts of gunfire as the crowd was beginning to leave. Fatah stone-throwers clashed with armed Hamas policemen.