NATO killed dozens of Taliban insurgents in an air strike on Sunday in Afghanistan's southeastern province of Khost, the provincial governor said. Violence has escalated in Afghanistan over the past two years after the ousted Taliban regrouped and launched their insurgency against the government and the foreign troops backing it. The pre-dawn raid was summoned to fend off an attack by the insurgents in Spera district, which lies near the border with Pakistan, Arsala Jamal said. "The Taliban attacked the headquarters of Spera district, killed two police and also damaged the building early this morning," he told reporters. "We had little force there and asked NATO for air support ... NATO air strikes killed 50 to 70 insurgents," he was quoted as saying by Reuters. NATO said the insurgents numbered about 100 and it had used helicopters in the attack. "Initial reports indicate that a small number of ANP (Afghan National Police) officers have been killed and wounded and the number of insurgents killed is in double-digit figures," it said in a statement. The Taliban said the group suffered no casualties, adding its fighters killed eight police in the attack on the district headquarters.