U.S.-led coalition and Afghan security forces killed nearly 60 militants during separate clashes in southern Afghanistan, the U.S. military and a police official said on Tuesday.

The combined forces killed 43 militants during heavy fighting in Qalat district of southern Zabul province on Sunday, the military said in a statement on Tuesday.

"[Afghan National Security Forces] and coalition forces on a patrol received heavy weapons, machine-gun and sniper fire from militants in multiple locations," the U.S. military said in a statement.

Afghan and coalition forces responded with small arms fire, rocket-propelled grenades and close air support, killing the militants, it said.

No Afghan or U.S.-led troops were killed or wounded during incident, it said.

In a separate incident, Afghan and international troops killed 16 Taliban insurgents and wounded six more during a gun battle in Nad Ali district of southern Helmand province on Monday, provincial police Chief Asadullah Sherzad told Reuters.

Violence has surged in the war-torn country, with some 3,800 people, a third of them civilians, killed as a result of the conflict by the end of July this year, according to the United Nations.

With files from Reuters