The U.S. military says coalition troops killed four militants in a strike on a bomb-making operation in southern Afghanistan.

A U.S. statement says the international forces were after a Taliban operative living just outside Kandahar city who has used roadside bombs to attack Afghan police and troops with the U.S.-led coalition.

The U.S. says Thursday's raid of the operative's compound turned into a gunbattle when militants fired on the troops, who killed four fighters and captured eight suspected militants.

Southern Afghanistan is the center of the Taliban-led insurgency, which has spread over the last three years in many areas of the country. These militants have increasingly relied on roadside bombs in their campaign against Afghan and foreign forces.