NATO said two gunman wearing Afghan defense forces uniforms attacked a military compound in Afghanistan's southern Helmand province Wednesday, shooting a vehicle and killing two coalition service members.
A NATO statement said coalition troops returned fire, killing both of the shooters.
NATO does not identify the nationality of troops who are killed, leaving that to the individual countries.
During the U.S.-led combat operations in Afghanistan there were dozens of instances of Afghan forces shooting American and other soldiers.
The attacks were blamed on a range of factors, from Taliban infiltration in the Afghan military to incidents of personal animosity or cultural misunderstanding between allied troops.
NATO declared an end to the combat mission in December and has been working with a reduced force of about 13,000 troops, the majority of them Americans, to advise, assist and train Afghan forces.