A group of ULFA (Independent) militants came on a motorcycle at about 2 AM at a Numaligarh petrol pump depot and pumped bullets in sleeping employees, killing one and injuring two others at Khelmati in North Lakhimpur district, SP P K Bhuyan said.
The injured were referred to the Guwahati Medical College Hospital.
Eight empty cartridges of AK-47 rifles were found near the spot, Bhuyan said.
In another incident, an ULFA(I) cadre was killed in an encounter with police while three others managed to escape at Betonisuk in Dibrugarh district, a police spokesman said.
An AK-56 rifle was recovered from the slain militant and search operations were on to nab the three militants who escaped, the spokesman said.