The ultras led by self-styled 'Lieutenant' Chiran Debbarma surrendered to Dhalai Superintendent of Police R R Debnath and deposited two AK series rifles, six magazines and 200 cartridges.
The other two insurgents were identified as Mangal Tripura and R Reang.
During preliminary interrogation, they revealed that they fled from their base camp at Chittagong Hill Tract of neighbouring Bangladesh in the wake of food and fund crisis.