The U.S. coalition says its forces have killed 43 militants in southern Afghanistan.

The coalition said in a statement that Afghan and U.S. troops battled the militants in Qalat district of Zabul province Sunday.

It said militants ambushed the patrol before the joint force fought back and called in airstrikes that killed the militants.

Southern Afghanistan is the center of the Taliban-led insurgency. More than 4,700 people — mostly militants — have died so far this year in insurgency-related violence.