Updated

A political rally by the militant Palestinian group Hamas (search) turned violent Saturday, as supporters of the rival Fatah faction opened fire, sparking a melee that left more than 25 people wounded, a Palestinian official said.

The incident in the Maghazi refugee camp in central Gaza was the first instance of violence between rival Palestinian factions since the election of Palestinian leader Mahmoud Abbas (search) in early January.

Abbas has been holding talks with rival political factions, including Hamas, in hopes of reaching a truce agreement between militants and Israel.

The shooting occurred at an outdoor rally staged by Hamas to celebrate its victory in municipal elections in Gaza earlier in the week. Hamas' strong showing dealt a setback to Abbas' dominant Fatah (search) faction.

The Palestinian official, who spoke on condition of anonymity, said the Hamas supporters chanted victory slogans, angering Fatah supporters in the area.

One of the Fatah supporters opened fire, seriously wounding one Hamas supporter and causing shrapnel wounds to four others, the official said. Some 25 other people were hurt by knives, clubs and beatings in the ensuing melee, the official said.

No further details were immediately available.

While rival Palestinian factions have sporadically fought one another, such instances of fighting are rare, with the various groups all saying they are committed to ending Israel's occupation of the West Bank and Gaza Strip.