Three persons were killed and a child was injured following a hand grenade explosion in Thalangama area in Koswatta, the police said.
The incident occurred a short while ago on Thursday (09) morning.
According to the police, one of the victim has been identified as the person who detonated the hand grenade over a personal dispute.
The remains of the deceased, mother and the grand mother of the child, will be taken to the Colombo National Hospital for autopsy. The child has also been taken to the same hospital for treatments.