On a tip-off about the movement of the anti-talk NDFB faction ultras, police launched an operation at Maltijhora area, IGP (BTAD) L R Bishnoi told PTI.
One extremist was killed in the exchange of fire at around 12.30 pm, while two others injured fled away, Bishnoi said.
The slain insurgent was identified as NDFB(S) Dhubri 'platoon commander' Thaiju, the IGP said, adding, a pistol was recoverd from him.
A search operation has been launched for the injured cadres, he said.