At least seven people were killed and several injured in an explosion at an Indian fireworks factory in the Duttapukur area of West Bengal's North 24 Parganas district on Sunday morning, fire brigade officials said.

The Indian Fire brigade officials said the explosion was so powerful that it damaged several buildings in the area.

Speaking to media persons, locals said that the explosion took place inside a two-storey house around 10.40am in the Nilgunj area of Duttapukar. The factory was being run from a house illegally, locals claimed.

Rathin Ghosh, state food minister and legislator from the area, said police officers told him that seven or eight people died and around six people were injured.

"District police officials told me that seven or eight people died and five to six people were injured. I will visit the spot. Firecrackers were stocked in the building in which the explosion took place. This is not an area where crackers were made. The main manufacturing hub was the Narayanpur area of Nilgunj which is far away from here. Police had shut down all the cracker units at Narayanpur," Ghosh told the media.

West Bengal has witnessed several similar incidents in recent past.

In May, an explosion at a fireworks factory killed nine and injured seven at Egra in Midnapore district. At least, two of the deceased were women.

In May in another incident, at least three people were killed in an explosion at an illegal firecracker manufacturing unit in a residential area in South 24 Parganas district.

In December last year, at least three people were killed and two injured at a fireworks factory at Mohanpur village in the Nodakhali area of South 24 Parganas district.

Several incidents of explosions have prompted the state government to declare a new policy under which fireworks can be built only in industrial hubs. The process of setting up these hubs has started.

On 22 May, the West Bengal government set up a committee headed by the state's chief secretary to look into such ilegal units.