Suspected Taliban militants ambushed an Afghan police patrol in southern Afghanistan, sparking a firefight that left three fighters dead, a police official said on Thursday. The Afghan police were patrolling in Nad Ali district of the southern Helmand province when they were ambushed by militants late on Wednesday, said provincial police chief Ghulam Nabi Malakhail. Police returned fire, killing three militants, while one policeman was wounded in the clash, Malakhail said. Separately, two coalition soldiers were wounded after a roadside bomb struck their vehicle in the same region.Elsewhere in Helmand, Taliban forces engaged a coalition convoy on Wednesday, wounding one coalition soldier and damaging a vehicle, said military spokesman Maj Quentin Innis. Coalition aircraft fired on Taliban positions, but no assessment had been made of Taliban losses. Another coalition vehicle was hit by a roadside bomb in the southern Zabul province, slightly wounding two soldiers, Innis said. The nationalities of the soldiers were not immediately released.