Sgt. 1st Class Debra Richardson, a Resolute Support spokeswoman, said Saturday in a statement that another U.S. service member was wounded in the attack.
The statement said the attacker was a member of the Afghan security forces and initial reports indicate the assailant was immediately killed by other Afghan forces.
The two U.S. service members were medically evacuated to Bagram Airfield, where the wounded service member is undergoing medical treatment and is in stable condition, it said.
The incident is under investigation.
Richardson said the name of the service member who was killed would be withheld until next of kin is notified.