The US military has halted the training of Afghan government-backed militias for at least a month in order to change the process of vetting new recruits.
The move follows a string of attacks by Afghan soldiers and police on their international allies.
There have been 34 insider attacks this year, which have killed 45 international troops.
A main pillar of the international troop drawdown is for allied forces to hand over responsibility for the country's security to Afghans by 2014.
Lieutenant Colonel John Harrell, a spokesman for US special operations forces in Afghanistan, said the pause in training affects about 1,000 trainees of the Afghan Local Police, a militia backed by the government in Kabul.
He said: "The training of the ALP recruits has been paused while we go through this re-vetting process, to take a look at this process to see if there's anything that we can improve.
"It may take a month. It may take two months. We don't know."
Afghan Local Police forces who have already been trained will continue to operate, and the government will continue to recruit new members, he said.
A spokesman for the international military coalition in Afghanistan also said there was no set date for the training of the local police to resume.
The head of the Afghan special operations forces said there has been no pause to the training of his forces.
The programme 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 15 September we restart," Brigadier General Sayed Karim said.
The most recent insider attack took place last week when an Afghan army soldier turned his gun on Australian soldiers, killing three of them.
