Pakistani helicopter gunships attacked Taliban positions in the South Waziristan region on the Afghan border on Tuesday, killing six militants, intelligence officials and residents said. The attack came as the army pressed on with an offensive against the Taliban in their Swat valley bastion, about 350 km (220 miles) to the northeast of South Waziristan, in its most concerted attempt to push back an expanding insurgency. Speculation has been mounting that the army would soon turn its attention to South Waziristan, the headquarters of Pakistani Taliban leader Baitullah Mehsud and a major base area for his Afghan Taliban allies battling Western forces in Afghanistan.