Gunmen in south-western Pakistan have attacked five oil tankers carrying supplies to NATO troops in Afghanistan. The incident took place near the town of Mithri, in Baluchistan province which borders Iran and Afghanistan. District administration chief Muhammad Azam said unknown gunmen fired at five NATO oil tankers and two of them caught fire while oil leaked from three others. He said there were no injuries to drivers. NATO trucks and oil tankers are regularly the targets of arson attacks to disrupt two key supply lines that cross western Pakistan bound for foreign troops fighting in neighbouring Afghanistan.