KOLKATA: A fire swept through a six-storey building housing illegal shops in the eastern Indian city of Kolkata on Wednesday, killing 19 people who were unable to flee the inferno, local officials said.

Hundreds of firefighters gathered at the scene of the blaze at the Surya Sen market near the railway station in the centre of the former colonial capital, where decrepit and poorly maintained buildings are vulnerable to fires.

A total of 38 people who were sleeping in the building when the blaze broke out at around 04:00 am (2230 GMT Tuesday) were rescued. Many have been transferred to two city hospitals for treatment.

“We found dozens of people lying unconscious with severe burn injuries on the floors of shops and some died of suffocation in their sleep,” state fire services director Gopal Bhattacharya told AFP, adding that 19 corpses had been recovered.

The unlicensed shops clustered in the building were selling plastics, papers, and foam products which created acrid black smoke that impeded rescue efforts and led to the high death toll.

“The fire has been brought under control,” Bhattacharya told AFP around midday.

City mayor Sovan Chatterjee said the building had “illegal construction and the shops inside the building were opened without permission of the civic body”.

Firefighters said it was too early to pinpoint the cause of the blaze, but short-circuits caused by old and faulty wiring are frequently the source.

In March 2010 a huge blaze on one of Kolkata's most exclusive streets killed 43 while in late 2011 90 people were killed when a fire engulfed a city hospital.

In the 2010 fire on Park Street which shocked the city, many people fell or jumped to their deaths after finding that a top-floor fire exit leading to the roof had been locked.

The chief minister of West Bengal state, Mamata Banerjee, visited the scene of the fire. She expressed regret at the endemic flouting of fire regulations and building norms in the densely populated city of 14 million.

“Kolkata is a more then 300-year-old city with nearly eight lakhs (800,000) premises. Many illegal constructions have come up over the years,” she said as she announced an inquiry and compensation for the victims.

The families of the dead will receive 200,000 rupees (3,700 dollars).