In Afghanistan, at least 17 Taliban militants were killed when NATO and Afghan forces engaged the militants in a fierce battle in southern province of Zabul. The defence ministry said in a statement today that the fighting erupted after militants fired several mortars at an Afghan army position. It said the battle was backed by international forces' air support and lasted for one hour. Meanwhile, Afghan officials and NATO forces are jointly investigating a NATO air strike had inadvertently killed seven Afghan soldiers and policemen in northwestern province of Baghdis a few days ago. The air strike took place amid fighting in Badghis province as Afghan and U.S. troops were looking for two American paratroopers who disappeared in the area on Wednesday.