A bodyguard from Afghanistan's National Directorate for Security has shot dead an American soldier and an aid worker.
According to the BBC, the bodyguard opened fire after an argument with a small group of American soldiers and civilians in the northern province of Panjsher.
A third US soldier was wounded in the incident.
The bodyguard was shot dead by US troops who returned fire.
The Taliban has claimed responsibility for the attack but local officials say there was no evidence of Taliban involvement.