Officials say Afghan forces killed nine people, mostly civilians, by mistake during a raid on a house in eastern Nangarhar province.
Provincial governor Hayatullah Hayat says Tuesday that eight other civilians were wounded in the raid late Monday night in Chaparhar district.
Hayat said a local police commander was among the dead.
He said gunfire had been coming from the house that was raided, but the casualties were identified as mostly civilians once the operation ended.
An investigation was being conducted into how the operation resulted in civilian casualties.
Inamullah Miakhail, a spokesman for the hospital in Nangarhar, also confirmed that nine dead bodies were brought to the hospital from the raid.
Both Taliban and the Islamic States group are active in eastern Afghanistan.