The unidentified insurgents detonated the bomb at Khudengtabi area, about 100 km from here, at 2:00 PM when the policemen were escorting district superintendent of police E Priyo Kumar after he was returning from a meeting with Myanmar officials at the border town of Tamu, the sources said.
The SP was unhurt, but the policemen were injured by bomb splinters, they said.
This led to a heavy exchange of fire between the policemen and insurgents for almost an hour, they said.
It was not known if there was any casualty on the side of the insurgents.
No one has claimed responsibility for the blast. A combing operation was launched in the surrounding hill areas.
Last Saturday, insurgents had exploded seven bombs at the Kwatha Khunou area near Khudengtabai in which two Assam Rifles jawans and a civilian were killed.