KABUL on Wednesday, officials said.
A brief statement from the International Security Assistance Force (ISAF) said NATO and Afghan officials were assessing the incident to determine the facts. It gave no further details of the incident.
Kapisa Governor Mehrabuddin, meanwhile, confirmed to Pajhwok Afghan News the green-on-blue attack happened in the Taamir Bazaar area of Tagab district.
A number of civilians were also wounded in fire from both sides, the governor said, adding that a joint team was investigating the shootout.
On the other hand, the Taliban said seven Afghan and four American troops were killed in the insider assault, Eight civilians were killed and five others wounded, the movement claimed.