KARACHI (Agencies) - Gunmen on Thursday torched six oil tankers in Shikarpur carrying fuel for NATO troops in Afghanistan, police said. Gunmen attacked the vehicles, parked at a roadside restaurant near Shikarpur, police official Ashraf Chandio said. The assailants fired several rounds of bullets on the vehicles with automatic weapons and after setting them on fire fled on motorbikes, Chandio said, adding that there were no casualties. No group has claimed responsibility for the attack. It was the first such attack in Sindh in nearly two and half months. Taliban and Al-Qaeda-linked militants frequently launch attacks on NATO supply vehicles in Pakistan, which borders landlocked Afghanistan. Pakistan is the largest single route into Afghanistan for supplies and equipment required by foreign forces, although the United States has increasingly tried to find alternative routes through Central Asia.