An army officer and two ULFA militants were killed in an encounter inside a reserve forest in upper Assam's Tinsukia district on Sunday.
Based on a tip-off, the army's Gorkha regiment raided the Mechaki reserve forest area at Hankhati where the militants, including hardcore ULFA ultra Joond Bhuyan, involved in several heinous crimes, were sheltered.
As the troops approached the area, the militants opened fire and the securitymen retaliated, leading to a heavy exchange of fire for nearly an hour.
In the shootout, Captain S Choudhury sustained grievous injury and was airlifted to the air force hospital at Roroiya where he was declared dead while Bhuyan managed to escape.
Bhuyan's close aides, Chandan Dohotia, alias Getley, and Tutu Moran, were killed in the encounter.
One AK-47 rifle was recovered from the spot.
The army rushed additional troops to the area to continue the search operation.