There was no claim of responsibility but the Taliban have mounted similar attacks to avenge US drone strikes killing militant commanders in Pakistans northwest and to protest against the US-led war effort in Afghanistan.

The first vehicle was attacked in the Mangochar area, 20 kilometres south of Quetta, capital of oil and gas rich Balochistan province, which borders Iran and Afghanistan.

“Two gunmen riding a motorbike stopped a Nato container, ordered the driver and his helper to leave the vehicle and then opened fire on it,” local tribal police official Aziz Faisal told AFP.

In Baghbana, 280 kilometres south of Quetta, gunmen opened fire on another Nato container, killing the driver and wounding a 12-year-old boy.

“The gunmen also torched the container and escaped,” another tribal police official, Muhammad Azam said.

Police confirmed Fridays attacks, which came weeks after Pakistan on October 10 reopened the main northwestern land crossing into Afghanistan used by Nato supply convoys.

The border had been shut on September 30 after a cross-border Nato helicopter strike killed two paramilitary soldiers in northwest Pakistan, but a second crossing at Chaman in the southwest remained open.

Balochistan is rife with Islamist militancy, sectarian violence between majority Sunnis and minority Shiite Muslims and a separatist insurgency.

Baloch rebels are demanding political autonomy and a greater share of profits from the regions wealth of natural resources.