The attackers stormed Dimasa tribal-dominated Bonkhai village in the district and set ablaze nearly all the houses.
The attackers subsequently sprayed bullets as people tried to douse the fire, killing one person on the spot and injuring three others.
The district has witnessed wide-spread violence since April with insurgent outfit Dima Halam Daoga (Halam) attacking security and railway personnel. It also witnessed ethnic clashes between Dimasas and Zeme Naga tribals, which claimed more than 40 lives so far.