At least eight persons were injured, four of them critically, when explosions ripped through two scooters at a market populated with toy shops in Kanpur on Wednesday evening.

The explosions were heard 500 metres away and at least four shops near the blast site at Misri Bazar developed cracks.

Joint police commissioner (law and order) Ashutosh Kumar said: “The blasts in the two parked scooters took place around 7.15pm in the Misri Bazar area under Mulganj police station. Several people were injured, including a woman.... Our forensic team is present at the scene. We are investigating the cause.... We will speak to those using the scooters. Whether this is an accident or a conspiracy will only be known later.”

Four of the injured persons have been sent to King George’s Medical University in Lucknow. Sources said they had suffered over 50 per cent burns.

Those critically injured have been identified as Mohammad Riyazuddin, 70, Mohammad Suhana, 70, Mohammad Abdul, 60, and Ashwini Kumar, 50.

Kanpur police commissioner Raghuvir Lal said: “All police teams have been activated. There is a firecracker market in this area only. But we need to conduct a thorough probe to reach a conclusion.”