Nagaon, May 18 (ANI): At least three people were injured after a grenade blast triggered off late on Tuesday evening outside a hardware store in Nagaon district of Assam. The grenade was set off by some miscreants in the Raha area of Nagaon. The injured were rushed to the Nagaon Government Hospital. Nagaon Director Inspector of General (DIG) Mukesh Sahay indicated that ULFA could be behind this incident.