A BSF jawan was killed and two Assam Rifles personnel suffered gunshot wounds Manipur's Serou area, the Army said on Tuesday.
The injured have been air evacuated to Mantripukhri and search operations are in progress, the Army's SpearCorps headquartered in Dimapur said on Twitter.
Further details will follow, it said.
"Extensive area domination operations by Assam Rifles, BSF & Police undertaken in areas of Sugnu/Serou in #Manipur... Intermittent firing between Security Forces & group of insurgents took place throughout night of 05/06 June. Security Forces effectively retaliated to the fire," it posted on Twitter.