An armed gang carried out the first attack on a secondary southern supply route for foreign troops in Afghanistan, as thousands of lorry drivers continue to boycott the main route through the Khyber Pass.

Police revealed yesterday that at least three gunmen attacked a fuel tanker bound for Afghanistan on Tuesday just east of the Pakistani city of Quetta, shooting and wounding the driver and spilling 60,000 litres of fuel.

Militants also fired two rocket-propelled grenades yesterday at a convoy of more than 150 lorries as it set off on the northern route from the northwestern city of Peshawar towards the Khyber Pass, local officials said.

They were the latest in a series of bold attacks on the supply route through Pakistan in the last month that have accelerated efforts by Nato to open a “northern corridor” through Russia and Central Asia.

About 75 per cent of US military supplies in land-locked Afghanistan and a smaller, though significant, proportion of Nato's are shipped into the Pakistani port of Karachi and then taken overland across the Afghan border.

Most are driven via the Khyber Pass and the border town of Torkham to Kabul, the Afghan capital, but some are taken by lorry to southern Afghanistan via Quetta and the border town of Chaman. Pakistani authorities were forced to close the Khyber Pass route for nine days last week after militants carried out their biggest attack yet on the supply line, burning at least 260 vehicles on two consecutive nights.

They reopened it on Monday but the Khyber Transport Association, which claims to represent 3,500 lorry owners and drivers, refused to resume taking Nato and US supplies because of the recent security problems.

They are especially concerned about the lack of security at the growing number of freight terminals on the ring road around Peshawar, where lorries typically wait for the night before proceeding to Kabul.

There were at least five attacks on the terminals last week alone.

Haulage firms say that some lorries are now moving through the Khyber Pass but the association, which represents about 60 per cent of the vehicles that ply the route, is still effectively on strike.

The strike appears to be about fuel prices and other commercial issues as well as security, according to sources at two haulage firms in Peshawar.

Pakistan's paramilitary Frontier Corps, which escorts the supply convoys, is also struggling to take more than 100 vehicles across each day, compared with 300-400 before the recent attacks, the sources said.

Police said that it was too early to tell who had carried out the Quetta attack. The surrounding province of Baluchistan is also in the grip of a local separatist insurgency led by ethnic Baluch rebels. Nato and US officials admit that they are concerned about the attacks but insist that their supply lines are durable and flexible.

Lieutenant-General Jim Dutton, deputy commander of Nato-led forces in Afghanistan, told a news conference yesterday: “I wouldn't want to belittle the effect because clearly the destruction of any supplies has an effect [but] it is not a measurably important effect on our operation.”

Times Recommends

• No apology for Germany’s own Nazi victims
• Intricate web of fear and hope tying down deal
• Victims remembered a year after Mumbai attacks