Kolkata: A low-intensity blast took place inside a medicine shop in at Kamarhati in the northern fringes of the city on Sunday afternoon as the state celebrated Mahanavami of Durga Puja.
North 24 Parganas district police said there was no report of any casualty in the incident.
A bag kept inside the shop went off around 1 pm and preliminary investigation suggested that there were some illegal firecrackers inside the bag, a senior police official said.
"A team of forensic experts will soon visit the spot. We have registered a suo motu case and started an investigation," he added.
According to officials, CCTV footage showed a young man wearing kurta and pyjama entering the medicine shop with a handbag and leaving the shop without it.
The CCTV footage showed the bag exploding minutes later. We are verifying the CCTV footage and trying to ascertain who the man was, the official said.
The shop has been cordoned off and sniffer dogs besides the forensic team are being sent to the spot, he added.
