The incident occurred last evening at South Point of Zunheboto town when NSCN(K) cadres allegedly started firing and lobbed grenade at a house where six members of the rival NSCN(Khole-Kitovi) group were holding a prayer meeting.
In the firing, a teenaged boy died on the spot due to bullet injuries. The deceased was the son of a civilian in whose house the prayer meeting was held.
Two other civilians, including a student of Patkai Christian College, Dimapur, were injured as the gunfight between the two groups continued for about 15 minutes, police said.
The condition of the injured was stated to be out of danger.
The NSCN (Khole-Kitovi) sources said one of their cadres was also injured in the firing.