By Syed Shoaib Hasan
BBC News, Islamabad
Supply routes through Pakistan are becoming increasingly insecure
Lorry drivers in north-west Pakistan say they will no longer deliver supplies to Nato and US-led forces in Afghanistan due to worsening security.
The move follows a spate of hijackings and attacks on their vehicles by Taleban militants.
At least 75% of overland supplies to foreign forces in Afghanistan travels through North-West Frontier Province.
The supplies are critical for troops in an increasingly drawn-out campaign against Taleban insurgents.
A convoy of trucks left the city of Peshawar carrying equipment for Nato and coalition forces early on Monday morning.
Escorted by dozens of paramilitary troops, drivers say it will be the last such supply convoy for now.
This is due to a decision by the local transport association to cease such operations.
Since September 2008, the Taleban in Pakistan have targeted vehicles carrying supplies for foreign forces in Afghanistan.
They have hijacked lorries, stolen their cargo and kidnapped their drivers.
Shakir Afridi, president of the Khyber Transport Association, said the dire security situation made it impossible to continue.
"This time our vehicles are with the convoy because they were already laden with goods," he said.
"But because of the increase in the number of attacks by the Taleban, we will not be a part of any convoy to supply goods to coalition forces from now on.
"The government must bring the situation under control before we continue."
Mr Afridi said that transport companies would review their decision if the government was able to regain control of the route to the Afghan border.
The decision is likely to be a blow to Nato and coalition forces who currently rely on shipments from Pakistan, but who are urgently looking for alternative supply routes.