QUETTA: A government administrator says unidentified gunmen in southwestern Pakistan have attacked and set alight two Nato oil tankers that were traveling to Afghanistan.

Abdul Aziz says the tankers were attacked Thursday as they were heading to the border town of Chaman in southwestern Balochistan province.

Chaman is one of the main crossing points for Nato supplies.

Militants and criminals in Pakistan frequently attack trucks carrying supplies for US and Nato troops.

The supplies typically arrive in Pakistan's port city of Karachi and travel overland to Afghanistan.