UPPER DIR - Hundreds of Afghan militants again attacked the border areas of Upper Dir by opening indiscriminate fire at the residents, besides setting ablaze a government school in the wee hours of Friday. For the second time in just three days, Afghan militants equipped with sophisticated arms besieged border areas of district Upper Dir. On Wednesday, militants raided Shaltalu checkpost. While in the fresh assault, they attacked Nusrat Darra by opening indiscriminate fire at the local population. Nusrat Darra is 10 kilometres from Shaltalu area. Official sources said again it were Afghan militants who re-attacked the border area, adding that they were hundreds in number and were well-equipped. They said the militants besieged the area and also torched a government primary school. After the attack, reinforcements and helicopter gunships had been moved into the Nusrat Darra to quell the attack. They shelled militant positions. Resultantly, five militants were killed and several other sustained injuries. The local administration has closed government-run schools at Shahi Kot, Bansahi and other adjoining areas. At least 28 policemen, eight civilians and 45 Afghan militants have been killed in the clashes started on Wednesday. Agencies add: Police earlier Friday told AFP that Shaltalu was under control. The area is in complete control of our troops. We have started a search operation, Rehman had told AFP. Rahim Gul, another police official at the nearby Barawal police station, confirmed the latest attack. After the first clash, Pakistan Wednesday conveyed strong concern to the Afghan ambassador to Islamabad, calling for stern action by Afghan and US-led Nato troops to crack down on militants in eastern Afghanistan. Shaltalu and Nusrat Darra are surrounded by mountains and forest, about six km from the border with Afghanistans Kunar province. The Tehreek-e-Taliban Pakistan claimed responsibility for the securitypost attack that appeared to signal that the group was adopting a new strategy of carrying out large-scale attacks on government and army targets. Up to 40 to 50 of our fighters took part in the operation, Ehsanullah Ashen, TTP spokesman, told Reuters by telephone from an undisclosed location. None of our fighters were killed. The TTP has previously brought fighters from across the porous border with Afghanistan - where it has allies - to attack Pakistani security forces, but none were on the same scale as the Dir operation. Deputy TTP leader Fakir Mohammed said the group with close ties to al Qaeda had changed strategy and would now focus on large-scale attacks only on state targets like the one in Dir. According to a media report, the Deputy TTP leader said: Our new strategy of launching big attacks on military installations was aimed at causing demoralisation in the ranks of the security forces and tiring of the government. A new TTP game plan may complicate the armys efforts to weaken the group, which has stepped up suicide bombings to avenge the killing of Osama bin Laden by US special forces in a Pakistani town on May 2.