Three people were killed in an explosion in a house in Kakori, on the outskirts of Lucknow, on Monday.
Ram Sharan, Mohammad Nasir and his wife died after some explosives kept illegally detonated around 11 am, police said.
The house, belonging to Sanjay, was reportedly being used as an illegal cracker factory, and it collapsed completely due to the impact of the explosion.
Senior police officials rushed to the spot from Lucknow.
Rescue operations are underway as a few persons are feared trapped inside the two-storeyed house. Several houses in the vicinity were also damaged due to the explosion.
Owner of the house Sajay Lodhi told the police that he had rented the house to Naseer and his son Mushir. He said he was unaware that they were involved in illegal manufacturing of firecrackers, IANS reported. Villagers told police officers that Naseer and his wife were present in the house at the time of explosion.