The number of injured persons has risen to 12 in the explosion outside a mall on Zoo Road in Guwahati on Wednesday.
"A grenade blast took place at 8 pm. An investigation is underway," said Deepak Kumar, Guwahati Commissioner of Police.
Two unknown bike-borne suspects lobbed a grenade on state police troops and fled the spot.
The area has been cordoned off and police is present at the spot. The injured have been referred to Guwahati Medical College Hospital for treatment.
Further details are awaited. (ANI)