At least 17 militants were killed Thursday when troops backed by helicopter gunships destroyed rebel hideouts in Swat valley, the army said. Gunships targeted the strongholds of fighters loyal to Taliban cleric Maulana Fazlullah in a follow-up to Wednesday's operation in the same region which killed 30 militants, an army spokesman said. "Today troops backed by helicopter gunships killed at least 17 militants including three commanders of Fazlullah," Major Nasir Ali told Agencies.