The explosion occurred at around 8 p.M. Last night when two motorcycle borne suspected militants hurled the grenade at the oil pump at Haokha village.
The two managed to escape under cover of darkness, the sources said.
The injured have been identified as Th Kumar (54) and S Khelen (50), sources said.
He police suspect that the militants might have exploded it in connection with monetary demand from the pump owner who was not available for comment.