Acting on a tip off, the Assam Rifles along with the Assam police launched an operation at Kalakhal jungle area yesterday.
Four AK-47 rifles, six magazines, 122 rounds of AK-47 bullets, one 9-mm pistol, two 12-bore rifles, one single-bore rifle, four rounds of pistol and revolver bullets were recovered, police said.
Objectionable documents, cell phones and PAN cards were also seized from the four militants identified as BNA self-styled 'commandant' Rajesh Charki from Mizoram, the outfit's secretary Arnajoy Reang (Tripura), Lowerjoy Reang (Mizoram) and Biloram Reang from Cachar, they said.
Ethnic group Bru is one of the 21 Scheduled Tribes incorporated as Reangs in the list and are found mainly in Tripura and also in Mizoram, Assam, Manipur and Bangladesh.