The miscreants attacked Lahorijan border outpost, manned by personnel of 6 Assam Police Battalion and injured the constable, Karbi Anglong superintendent of police M J Mahanta told PTI.
Assam police personnel retaliated and the firing continued for more than ten minutes.
The incident took place when Assam police was conducting search operations in the area. Empty cartridges of AK-series rifle was found from the incident site, Mahanta said.
The injured constable, identified as Rajesh Teron, was admitted to Diphu Civil Hospital and later shifted to Guwahati Medical College for treatment, he added.