A self styled sergeant major of ULFA was killed on Tuesday in an encounter with police, while another militant of the outfit was apprehended, police said.
ULFA cadre Nitul Gogoi was arrested with a pistol at Namrup in the district and he led the police to the outfit's 28th battalion self styled sergeant major, Biplab Baruah's hideout at Jokai Borbil village.
As police surrounded the village, Biplab, who was hiding in a house, started firing at the personnel in a bid to escape. Biplab was killed in retaliatory firing, they said.
A universal machine gun (UMG), one magazine with seven rounds of live ammunition and five detonators were recovered from the slain extremist.
Biplab was part of the ULFA ceasefire group, but he had escaped from a designated camp with a UMG, they said.