A hardcore Ulfa militant was killed and three others were injured in an encounter with security forces in Assam's Tinsukia district on Sunday, police said.
Acting on a tip-off about the presence of a group of Ulfa militants, a joint team of Army's 8 Garhwal Rifles and police launched an operation at Ratnapur Haigarh village, they said.
A heavy exchange of fire took place between both the sides in which one militant was killed and three other militants were injured, they said.
The injured militants were yet to be captured and operations were on to nab them, police said.
An AK-47 rifle, two grenades and Rs 50,000 in cash was recovered from the slain militant, they added.