Backed by helicopter gunships, Pakistani troops on Tuesday killed 15 militants and captured six others during an operation against the banned Lashkar-e-Islam group in the restive Khyber tribal region in the northwest after authorities imposed a curfew in a key district there.

The security forces launched the operation in Bara sub-division of Khyber agency this morning after curfew was clamped on the region for an indefinite period.