Militant attacks killed six Pakistani security officers on Monday, a day after the Taleban chief warned of more terrorist strikes if the army did not stop its offensive against insurgents along the Afghan border. Many schools around the country reopened after being shuttered for a week following warnings of insurgent strikes and a double suicide bombing at a university in the capital. The army moved into South Waziristan tribal region nine days ago vowing to crush the Pakistani Taleban, a militant network it says is behind 80 percent of the suicide bombings in Pakistan. Washington backs the operation because militants in the northwest region are believed to shelter al-Qaida leaders and attack Western troops in Afghanistan. Militants assaulted security officials in Toraware village overnight, killing two and wounding four in a three-hour shootout in the area some 60 miles (95 kilometers) north of South Waziristan, police officer Mir Chaman Khan said. Some 10 insurgents were believed to have been killed. In Bajur, a tribal region further north, Taleban fighters attacked a checkpoint at Matthak village, killing four security officials. Seven militants died in the clash, said Syed Ghulam Rasool, a local government official. The militants also attacked security check posts at Khar, the main town in Bajur, and Siddiqabad, an adjoining village, wounding at least three security personnel. Militant attacks in Pakistan have surged this month, killing more than 200 people, as the Taleban have tried to avert the army offensive in South Waziristan. The army has deployed some 30,000 troops to South Waziristan to take on an estimated 12,000 militants, including up to 1,500 foreign fighters, among them Uzbeks and Arabs. The UN says some 155,000 civilians have fled. Pakistan has claimed a string of successes during a 10-day offensive to crush Tehreek-e-Taleban Pakistan (TTP) in South Waziristan, pressing its most ambitious battle yet in a tribal area infested with Al-Qaeda-linked rebels. Pakistan forces killed 19 militants in an intense clash in South Waziristan on Monday while insurgents aiming to divert the army's attention launched a raid in another northwestern region, officials said.