The fighting took place as troops, backed by helicopter gunships, carried out a search operation around the town of Bara in the Khyber tribal district bordering Afghanistan. "Four paramilitary soldiers were martyred and seven others were wounded in today's fighting," a senior security official told AFP. "At least 39 militants were also killed," he said. Four civilians also died when a mortar shell hit a house, a government official said. "Four civilians were killed in the day-long gunfight when a mortar shell hit their house," Khyber's deputy administration chief Syed Ahmed Jan told AFP. It was not immediately clear who fired the mortar shell, he said. A senior paramilitary official said the militants belonged to the Taliban-linked Laskhar-e-Islam group that is led by warlord Mangal Bagh. Independent verification of the incident is not possible as access to the area is restricted by the military.