One person was killed and three others were injured in a grenade blast on Sunday morning in Udalguri district, police said.
The grenade exploded near a market in Rowta area in Udalguri killing one person on spot while three others sustained serious injuries, they said.
The deceased was identified as Ram Chandra Barman, a scrap dealer, police said.
The injured persons were admitted to a local hospital.
Senior police and civil officials have rushed to the spot and the matter is being investigated.