QUETTA: Unknown assailants opened fire on six oil tankers heading toward Afghanistan near the Mach locality of tehsil Bolan in Quetta city late on Thursday, setting them ablaze.

Four oil tankers were left completely gutted as a result of the attack.

The Afghanistan-bound containers were passing through Quetta, carrying oil and other logistical materials for Nato forces.

Gunmen attacked the trucks when the drivers stopped along a hotel on National Highway.

Fire tenders had been called in from Quetta and Sibbi, officials said.