Abdul Aziz Bangulzai said armed militants initially opened fire on tankers and then set them on fire in the Bolan district.

"Four militants on two motorcycles attacked (the) NATO supply and managed to escape from the spot," Bangulzai said.

He said no one was injured, but the tankers were destroyed.

There was no immediate claim of responsibility, but militants in the region have frequently targeted Pakistani security forces and supply trucks headed for Afghanistan in an effort to undermine U.S. and NATO efforts there. More than half of the supplies for NATO forces in Afghanistan travels through Pakistan.