"One US service member assigned to the NATO Resolute Support mission was killed in Afghanistan on October 4," the release said.
Resolute Support and United States Forces-Afghanistan Commanding General Scott Miller said forces on the ground remain committed to their mission.
The name of the soldier will not be released for at least 24 hours after the family is notified, the release said.
The NATO's mission in Afghanistan was launched in 2015. It includes over 13,000 servicemen who are providing training and advice to the Afghan security personnel in their fight against terrorism, particularly against the Taliban* group.
Afghanistan has long been in a state of turmoil, with the government fighting the terror groups.
*Taliban is a terrorist group banned in Russia