The incident occurred when some suspected GPRN/NSCN gunmen stopped an auto rickshaw carrying four persons near the SP office and tried to drag them out yesterday.
As some occupants of the three-wheeler fired a few rounds, the attackers responded with firings killing a Karbi youth on the spot. Two others were shot dead after the assailants chased them as they were running towards the Dimapur civil hospital.
The fourth occupant, who was suspected to be a NSCN(K) member, also received bullet injuries, police said.
In the shooting incident on the busy road, two passers-by, who were standing in front of a taxi counter, were also hit by stray bullets, but they are out of danger, police said.