At least six Palestinians were killed when tens of thousands of Fatah supporters held a rally in Gaza.
More than 100,000 Palestinians gathered in Gaza City on Monday to mark the third anniversary of the death of Yasser Arafat, who founded Fatah.
The demonstration was watched closely by Hamas, which routed Fatah in a brief Gazan civil war in June and has since limited public events by the rival faction. Toward the end of the rally, violence broke out as Hamas began to disperse the crowd and six Fatah supporters were killed by gunfire. Some 55 were wounded, several critically.
Fatah said one of its supporters was shot dead by Hamas militiamen en route to the event.