Withdrawal of Western forces from Afghanistan may be speeded up

The retreat of Western forces from Afghanistan could come sooner than expected, the head of Nato said, as he conceded that the Taliban strategy of "green on blue" killings - Afghan security forces turning on their trainers and mentors - had been successful in sapping Western morale.

Amid growing pressure for a faster withdrawal from Afghanistan, Nato secretary general Anders Fogh Rasmussen said the options were being studied and should be clear within three months.

"From now until the end of 2014 we will see announcements of redeployments, withdrawals or drawdown … if the security situation allows, I would not exclude the possibility that in certain areas you could accelerate the process," he said.

Rasmussen admitted that the killings of almost 50 allied troops this year in "green on blue" attacks had damaged the relationship between the international forces and the Afghan police and military. "There's no doubt insider attacks have undermined trust and confidence, absolutely," he said.

Nato aims to have an Afghan security force take over responsibility for the country in just over two years' time when the US-led combat operations are scheduled to end.

Amid argument among analysts as to what has been behind the stream of "green on blue" attacks, Nato officers on the ground have reportedly ascribed them mainly to disgruntled and embittered members of the Afghan security forces with grudges against Western mentors.