A joint team of police and CRPF's COBRA unit busted the NDFB(S) camp inside Manas Reserve Forest under Panbari Police Station, IGP Dr L R Bishnoi told PTI.
Acting on a tip off, the police picked up NDFB(S) linkman Sombaru Basumatary, from Amlaiguri village and during interrogation he confessed to supplying ration to the ultras' camp and agreed to take the force to the spot.
Sombaru was carried by police personnel on shoulders out of the jungle and taken to hospital where he succumbed to his injuries.
The security personnel and NDFB(S) insurgents exchanged fire for 15 to 20 minutes before they escaped taking cover of the dense forest.
Police then found a temporary camp and preliminary investigations revealed that NDFB (S) vice chairman G Bidei along with six militants - Bidai, Batha, Jarimin, Birbai, Jwetwn and Jewthi - had been staying there, the IGP said.