The decision to cut back on joint operations by international and Afghan forces raises crucial questions about the key plank of the exit strategy from the 11-year war which has proved costly in lives and money.

The move is also a significant propaganda coup for the insurgents, coming just after their assault on Camp Bastion which resulted in the destruction of warplanes worth US$200 million ($241.2 million).

For the British and coalition troops, the announcement in Washington will only highlight the mistrust which has been the inevitable consequence of 51 deaths inflicted by their supposed Afghan brothers-in-arms.

Adding to the uncertainty was the way the news of the order filtered out, with allies in the coalition seemingly kept in the dark by the United States and Nato high command.

Britain's Defence Secretary, Philip Hammond, clearly had not been told about it when he appeared before the House of Commons on Tuesday after the latest killings of two British soldiers by an Afghan in uniform.

Neither had the Afghans. Afzal Amaan, the head of operations at the Defence Department in Kabul, said yesterday: "We haven't heard officially from the foreign forces about this. It will, of course, have a negative impact on our operations. Right now, foreign forces help us in air support, carrying our personnel, wounded and dead out of the battlefields, in logistics and training."

Major Adam Wojacjk, a spokesman for Isaf (International Security Assistance Force), acknowledged that the "vast majority" of the 350,000-strong Afghan security forces would be affected by the suspension of joint operations for units smaller than battalion strength, where most training takes place. This means, in effect, that Afghan forces will have to undertake missions at a time of a renewed insurgent offensive without support from Nato.

The West's exit from the conflict is based on Afghan forces taking over control of security by 2014.

The rush for a withdrawal from Afghanistan has created the conditions to allow the Taleban to infiltrate the local security forces, Afghan and some Western military commanders insist, with around 7000 recruits for the Afghan police and army having to be processed every month. Since the rise in the "green on blue" attacks, vetting has been tightened up, and one in 35 applicants is said to have been rejected. One Afghan official said 420 out of the 15,000 who applied to join the army in the last seven months appeared to have the sole aim of murdering Western troops.

"They say we should be doing more to stop these people getting in, but hundreds of suspects have been detected by the NDS [Afghan intelligence] and stopped from joining," said Selim Mohammed Naimtullah, until recently an official at the Ministry of Interior in Kabul. " The problem we face now is not screening, but this decision to stop carrying out operations together. If this continues we are going to face a very dangerous future."

- Independent