More members of the NATO-led forces in Afghanistan have been killed in shooting involving an apparent Afghan ally. The deaths appear to be only the latest in a series of so-called "green on blue" killings.
Four soldiers were killed in Sunday's attack, which appeared to have been carried out by members of the Afghan police force.
At least one attacker involved in the shootings was reported to have been wearing an Afghan National Police uniform.
"What I can confirm is that an individual believed to be an Afghan policeman turned his weapon against the NATO soldiers, killing four in the southern part of Afghanistan," alliance spokesman Charlie Stadplander said.
US Army Major Adam Wojack said the sequence of events was unclear, with four of the six soldiers killed and the other two wounded.
It is believed that the NATO forces retaliated after coming under fire from police. An attacker wearing an Afghan police uniform was shot and killed, while several other police deployed to an observation post had fled.
The nationalities of the victims were not immediately apparent but Afghan officials said the incident took place in Mizan district of Zabul province, where most troops are Americans and Polish.
At least 51 foreign military personnel have been killed in "insider" attacks this year.
Two British soldiers were killed in a similar attack on Saturday in the Helmand province.
The rise in such attacks has meant that the training of new recruits to one Afghan police unit, recruited specifically to fight the Taliban, has been suspended.
Afghan authorities have arrested or sacked hundreds of soldiers for suspected insurgency links.
rc /mkg (AFP, dpa, Reuters)