KOLKATA (AFP) - A fire swept through a six-storey building housing illegal shops in the eastern Indian city of Kolkata in the early hours of Wednesday, killing 19 workers sleeping in the building, local officials said. Hundreds of firefighters battled the flames at the Surya Sen market near the railway station in the centre of the colonial-era capital, where decrepit and poorly maintained buildings with faulty wiring are vulnerable to fires. A total of 38 workers were rescued while 19 died, mostly migrants from the eastern state of Bihar who were sleeping in the building when the fire broke out at around 04:00 am (2230 GMT Tuesday).

"The market had no fire extinguisher," state fire services minister Javed Khan said, confirming that one woman was among the dead. "The fire spread before the people sleeping there could understand anything."

Around a dozen people have been transferred to two city hospitals and five were in a critical state with burn injuries, he added.

"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.

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 number of deaths.

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

City mayor Sovan Chatterjee criticised "illegal construction" and unlicensed shops, while local legislator Sikha Mitra said she had complained about the building to the city authorities.

"I sent letters to the city mayor and the fire services minister highlighting the dangers of the market over the past two years," Mitra said. "My letters went unheeded."

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

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, 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 and expressed regret at the endemic flouting of fire and building regulations in the densely populated city of 14 million.

"Kolkata is a more-then-300-year-old city with nearly eight lakh (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).