A man in Afghan army uniform shot and killed a soldier from the NATO-led force in southern Afghanistan on Monday, the military said, giving no further details in line with policy.
"An individual wearing an Afghan National Army uniform turned his weapon against an ISAF (International Security Assistance Force) service member in southern Afghanistan on Tuesday, killing the service member," it said.
A spokesman was unable to provide information about whether the shooter was shot or managed to flee. It could not be verified if the shooter was an army soldier or merely wearing military uniform.
There have been repeated cases of members of the fast-growing Afghan security forces turning their weapons on international colleagues.
In what is thought to have been the deadliest incident of its kind, an Afghan air force officer killed eight US soldiers and a private contractor last month at a military training centre in Kabul.