Afghan soldiers backed by NATO forces and warplanes killed 18 Taliban militants in a series of clashes in southeastern Afghanistan, the alliance said Friday. Three NATO soldiers, three Afghan troops and an interpreter were also wounded in the fighting in Paktika province, near the Pakistani border, an International Security Assistance Force (ISAF) press release said. The statement said the combined forces came under small arms fire from a group of 25 to 30 insurgents in remote Bermal district.