A dispute over who should pay to protect Nato and US military supplies crossing Pakistan is hampering efforts to secure the main lifeline for foreign troops in Afghanistan.

Pakistan's Government, recently bailed out by the IMF, wants the shipping companies carrying the supplies to pay for the extra security on the main route from the port of Karachi via the Khyber Pass to Afghanistan.

Militants have staged several attacks on the route in the past month, torching 260 vehicles the week before last, and killing three people on the Khyber Pass yesterday.

The shipping companies, suffering from the global credit crunch, are reluctant to hire guards for the convoys, which account for 75 per cent of US supplies in Afghanistan and a smaller proportion of Nato's.

Local firms subcontracted to deliver the supplies blame the Government and each other for failing to secure freight terminals in the northwestern city of Peshawar from repeated attack. They also want Britain and the US to lend them money so that they can buy their own trucks instead of hiring individual owner-drivers.

Owner-drivers want more money to drive from Peshawar to Kabul because of the security risks. Those who have lost their vehicles in recent attacks want compensation. “It's a huge issue,” the head of a Pakistani haulage company that carries Nato supplies said. “We've got to get into a situation where everyone agrees it's a problem.” Nato and US officials say the recent attacks have not affected their military operations.

The dispute, however, highlights the fragility of the Pakistan route, which has closed several times this year, forcing Nato to accelerate efforts to open a “northern corridor” through Russia.It also illustrates the risks of subcontracting vital military logistics operations to an extent where it is unclear who is responsible for basic security.The recent attacks have destroyed 200 of the 700 to 800 long vehicles available to carry heavy military equipment.

The Khyber Transport Association, which represents 60 per cent of owner-drivers on the route, has also been on strike for a week, further limiting the supply of vehicles.

The recent attacks were apparently carried out by militants and criminal gangs from neighbouring regions who have upset the traditional tribal structures controlling the Khyber Pass.

But some Pakistani hauliers have also been blamed for failing to conceal military supplies or to provide enough guards at the freight terminals around Peshawar.

The international shipping companies declined to comment and all the companies involved asked that their names be witheld for security reasons.

Times Recommends

• Henning Mankell: ‘If Wallander was alive, I wouldn’t be a friend of his’
• Secret society's skull and crossbones for sale
• Nigerian leader vanishes after medical treatment