THE US military has halted the training of Afghan government-backed militias for at least a month in order to redo the vetting of new recruits after a string of attacks by Afghan soldiers on their international allies.

There have been 34 insider attacks this year - at least 12 in August alone - that have killed 45 international troops.

The attacks have cast doubt on the ability of Afghan and coalition forces to live and work together during a key time in the transition to Afghan control of security.

One of the pillars of the drawdown of international troops is for allied forces to hand over responsibility for the country's security to Afghans by the end of 2014.

Lieutenant Colonel John Harrell, a spokesman for US special operations forces in Afghanistan, said the pause in training affects about 1000 trainees of the Afghan Local Police (ALP), a militia backed by the government in Kabul.

"The training of the ALP recruits has been paused while we go through this revetting process, to take a look at this process to see if there's anything that we can improve," Lt Col Harrell said.

"It may take a month, it may take two months. We don't know."

Afghan Local Police forces that have already been trained will continue to operate, and the government will continue to recruit new members, he said.

The pause in training for the government-backed militias was first reported by The Washington Post.

Lt Col Harrell said the Americans last month also put a two-week pause on operations by the Afghan special forces to further vet those soldiers for any potential ties to insurgents.

He did not say whether any suspicious links were uncovered.

The international forces in Afghanistan have been revisiting both security for their forces and re-examining the backgrounds of the Afghan forces in the wake of the recent attacks on international troops.

The Post also reported that training of special operations forces had been halted, but a spokesman for the NATO training mission in Afghanistan, or NTM-A, which oversees this training said there has been no such pause.

"There has been no halt in training with NTM-A assets as they relate to special forces," said Major Steve Neta of the Canadian military.\

He also said no other training programs involving the traditional military or police have been halted for re-vetting.

The head of the Afghan special operations forces said there has been no pause to the training of his forces.

The program to train Afghan special operations forces had already been on break for the Muslim holy month of Ramadan and had been scheduled to restart in mid-September.

"It will continue. It is not ended at all. After the 15th of September we restart," Brigadier General Sayed Karim said.

The most recent insider attack took place last week when an Afghan army soldier shot dead three Australian soldiers.

The attacker fled and is stijl on the run.

Over the weekend, the US-led NATO coalition traded barbs with President Hamid Karzai over a joint operation carried out by Afghan and Australian troops to catch the insurgents responsible for the shooting in Oruzgan province.

In a statement issued late on Saturday, Karzai's office condemned an operation by international troops to go after the shooter, describing it as unilateral and saying it resulted in the deaths of a 70-year-old man and his 30-year-old son.

The US-led international coalition responded by saying that Afghan officials approved and supported the strike.