Afghanistan's defence ministry says it has arrested or sacked hundreds of soldiers, following attacks on foreign troops. It comes as the NATO chief expressed his concern over insider attacks by Afghan forces.
The ministry said the probe had lasted several months but did not announce how many soldiers were arrested or fired.
It also did not say whether the detained and fired soldiers were from Taliban strongholds in the south and east, simply that they were from all over Afghanistan.
"Hundreds were sacked or detained after showing links with insurgents. In some cases we had evidence against them, in others we were simply suspicious," said Defence Ministry spokesman Zahir Azimi, speaking to reporters in Kabul.
"Using an army uniform against foreign forces is a serious point of concern not only for the Defence Ministry but for the whole Afghan government," Azimi said.
Azimi said that Afghan president Harmid Karzai had ordered his country's forces to come up with ways to stop insider attacks.
Forty-five NATO soldiers have been killed by Afghans in uniform in 2012, compared to 35 last year.
Wednesday's announcement came as the NATO chief, Anders Fogh Rasmussen, telephoned Karzai to urge him to act.
A spokeswoman said Rasmussen outlined various measures to try to stop the attacks, including better counter-intelligence, cultural awareness training and a strengthening of vetting procedures.
Rasmussen "reaffirmed our continued commitment to the ISAF mission and emphasised that the strategy remains on track," said spokeswoman Carmen Romero.
"The secretary-general, however, also shared with President Karzai his deep concerns about insider attacks," she said.
Helicopter crash kills two NATO personnel
On Wednesday, two NATO personnel were killed when their helicopter crashed, in an area south of the capital Kabul largely under Taliban control.
"I can confirm that a helicopter crashed this afternoon in Logar province, in which two international security assistance force service members were killed," said spokesman Lt Col Hagen Messer.
"A small NATO helicopter flying on the battlefield made a forced landing when one of its pilots was injured in the hand by a bullet shot by the insurgents," Logar police chief Ghulam Sakhi Rogh Lewanay told the news agency DPA.
jr/kms (Reuters, dpa, AFP)