The militant was arrested late last night from the remote Torabil area under Rangapara police station during search operations by the police and troops of the Assam Rifles, Sonitpur Superintendent of Police Sanjukta Parashar said.
He has been identified as Ranjan Brahma and a hand grenade was recovered from his possession.
Meanwhile, a top NDFB(S) militant, the alleged mastermind of the December 23 attack on adivasis, managed to escape from the security forces dragnet during combing operations in Tharoibari village under Bishwanath Chariali police station last night, a senior police officer said.
Combing operations by the police and troops of Assam Rifles was on to nab the militant.
More than 80 NDFB(S) militants have been apprehended since the December 23 attack on adivasis which left 66 people dead in BTAD and Sonitpur districts.