The U.S. military says one of its service members and an American civilian were killed Wednesday in a shooting near a coalition base in the Afghan capital, Kabul.
Another service member and two U.S. civilians sustained injuries and were in stable condition, according to an official announcement.
The shooter, wearing an Afghan army uniform, was instantly shot and killed in retaliatory fire by international forces.
The victims were conducting duties as part of the larger NATO mission to train, advise, and assist the Afghan security services, said the U.S. military, adding an investigation is being conducted to determine the circumstances of the event.
"Any time we lose a member of our team, it is deeply painful" said General John Nicholson, commander of U.S. forces and the Resolute Support mission.
"Our sympathies go out to the families, loved ones, and the units of those involved in this incident,” he said, vowing such incidents will not deter U.S. and coalition forces’ mission to help Afghan partners create a better Afghanistan.
Other insider attacks
Earlier, Afghan Defense Ministry spokesman Dawlat Waziri told VOA the foreign military personnel were visiting an Afghan National Army base in Kabul when they came under attack.
In May, gunmen wearing Afghan soldier uniforms shot dead two Romanian military officers during a training session in the southern city of Kandahar.
Insider attacks involving Afghan and foreign soldiers have become rare in recent years because of joint preventive measures and protocols put in place.
However, such attacks within Afghan security forces are common. Late last month 12 Afghan soldiers were killed by two colleagues at a security outpost near the troubled northern city of Kunduz.
The shooters later facilitated the advancing Taliban to take control of the facility.
The insurgent group often claims shooters are its members who have infiltrated Afghan army and police forces.