Security forces have killed 15 terrorists and detained 60 others, the army said Sunday, in the first major action against insurgents under Pakistan's new government. Army spokesman Maj. Gen. Athar Abbas said five troops have been wounded in five days of fighting near the town of Hangu in the troubled northwest. Abbas said helicopter gunships were providing cover for troops on the ground. The army launched the operation Wednesday, three days after armed supporters of Pakistani Taliban leader Baitullah Mehsud killed 17 troops in an ambush in the area. Five militants were also killed in that clash. Abbas provided no details of how the militants were killed or captured in the operation, which the army has said will continue until the area is cleared of "miscreants." However, an army statement said five militants died in a failed assault on a military fort early Sunday. More than 100 militants attacked the Tora Warai fort after midnight, but were held off by the 29 paramilitary soldiers inside until army reinforcements arrived, it said. Army troops destroyed six vehicles belonging to the militants as they fled, it said. An estimated 20 militants were injured. The operation in Hangu, which borders Pakistan's militant-plagued tribal belt, is the biggest against violent Islamic extremists since Pakistan's new government took charge after winning elections in February. Leaders of the coalition government have favored seeking peace deals to curb the rising strength of groups linked to the Taliban and al-Qaida, a departure from the tactics of US-allied President Pervez Musharraf, who had relied more heavily on the military. US and Afghan officials blame the lack of pressure on the militants in Pakistan for a spike in violence in Afghanistan. The Pakistani strategy is also under pressure from Mehsud, who this week threatened to attack the provincial government if the operation in Hangu is not stopped. Days before the operation began, police arrested several suspected militants including an alleged aide of Mehsud. Prime Minister Yousuf Raza Gilani said Saturday that Pakistan, a key US ally, remained committed to fighting extremism but would not allow foreign troops to hunt down militants in its territory.