An NDBF militant was killed in an encounter with security forces in Assam's Sonitpur district on Sunday morning, official sources said.
Acting on a tip-off, the army and the police launched an operation in Chariduar area of the district and killed a militant identified as Pushpa Brahma.
Other militants, however, managed to escape as they fired back on the security forces.
A combing operation has been launched to nab the other militants, sources said.
Meanwhile, security in the district has been beefed up following intelligence inputs that the banned NDBF was planning to disrupt the forthcoming parliamentary polls.