NEW DELHI - At least 18 people were killed and more than 20 others sustained burn injuries in a devastating fire which gutted an illegal paper and plastic market in the eastern Indian city of Kolkata in the wee hours of Wednesday, a senior police official said.

"Some 18 people are confirmed dead in the fire which broke out in the six-storied Surya Sen market-cum-godown at the heart of the city around 3:50 am. The death toll may go up. The injured have been admitted to nearby hospitals where the condition of some are said to be serious," he said, on condition of anonymity.

Nearly 30 fire tenders took over three hours to bring under control the inferno which authorities have indicated could have been due to an electrical short circuit at an eatery on the first floor of the market building. "However, a probe has been ordered to ascertain the exact cause of the fire," he said.

Local TV channels showed footage of rescuers trying to bring out those trapped inside the market located at a congested area and smoke billowing out of the windows of the eatery.

The Fire Minister of the eastern state of West Bengal, Javed Khan told TV channels the market was "illegal" and that local civic authorities had earlier served the shop keepers with an eviction notice. "The market has only one exit point and those who stayed in the market at night were trapped after the fire broke out," he said.

State Chief Minister Mamata Banerjee visited the spot and surveyed the damages caused by the fire. She also assured strict action against those responsible for the fire.

Similar fires have claimed many lives in the city over the past decade.

More than 90 people were killed in December 2011 in a blaze at a hospital in Kolkata while in 2010 nearly 50 people lost their lives in a fire at the historic St Stephen's Court building on the city's upmarket Park Street area.