NATO says a man wearing an Afghan army uniform has turned his weapon on coalition troops, killing two service members.
NATO says the incident occurred on Thursday in eastern Afghanistan. No other details were disclosed.
The shooting is the latest in a rising number of attacks on NATO troops by Afghan police and soldiers or militants dressed in their uniforms.
The attacks have raised questions about the vetting of Afghan recruits and has heightened tension between foreign troops and their Afghan partners.
Last month, France suspended its training program and threatened to withdraw its forces from Afghanistan a year ahead of schedule after an Afghan soldier shot and killed four French soldiers on a base in the east.