A massive fire that swept through an illegal market early Wednesday in the eastern Indian city of Calcutta claimed 19 lives and injured more than 50 people authorities said.

The fire was detected at 3:50 a.m. at the Surya Sen market complex in central Kolkata's Sealdah area when the victims, mostly shop owners and workers, were sleeping inside. The market houses shops and storage units for inflammable objects such as plastic, paper and chemicals.

The fire was brought under control with more than two-dozen fire engines, but it is yet to be doused completely as of Wednesday afternoon, the Hindustan Times reported.

One woman and 18 men died so far, while some sustained severe burn injuries and others died of suffocation. More than 50 people have sustained serious injuries, the report said, and the death toll may climb.

West Bengal Chief Minister Mamata Banerjee, who visited the site following the incident, hinted at possible sabotage and ordered an inquiry.

“This is a very tragic incident. And it has happened because of unplanned construction in the area,” Banerjee said.

“Who knows that some people deliberately set the place on fire with an ulterior motive,” she said, adding: “We have ordered an inquiry. KMC, the fire department and the police will jointly conduct the inquiry and submit its report in three days,” the Times of India reported.

The reason for the fire is not yet known. Police officials said a short circuit may have sparked the fire.

Most of the victims were migrant workers from neighboring state Jharkhand and rural Bengal. The victims were taken to Calcutta Medical College and Hospital and to the NRS Medical College and Hospital. Two people admitted to the hospital are reportedly in critical condition.

A temporary camp has been set up in the area where Banerjee and some of her cabinet colleagues, including Urban Development Minister Firhad Hakim and fire services minister Javed Khan, are staying to oversee relief operations.

Khan said the building was unauthorized and blamed the previous Communist party government, which ruled the state for 34 years, for allowing unauthorized construction of the market.

In December 2011, around 90 people died in a fire that broke out at the AMRI hospital in the city. The previous year, 43 people died in a fire at the historic St. Stephen's Court building on the city's Park Street. In 2008, more than 2,500 shops were destroyed in a huge fire at one of the city's largest markets.