In an operation executed with intelligence inputs, the Assam Rifles raided a hideout of the JNB in the dense jungles between Lungting and Hatikhali East of village Hatikali under Langting police station, an Assam Rifle official said.
The paramilitary force team closed in on the hideout when the extremists fired at random and tried to run away.
In the retaliatory firing, two ultras were neutralised, while the third fled, he said, adding, one AK-56 rifle, three single barrel rifles and one air gun pistol were recovered from the hideout.
The activities of the underground group was revealed recently and it is reported to be operating in Dima Hasao for the past few months.
The Assam Rifles has been instrumental in bringing peace to the district for its socio-economic development with extensive counter-insurgency operations, the official added.