A fire gutted rows of shanties beneath Durgapur bridge in New Alipore on Saturday evening.

The leaping flames next to a busy thoroughfare forced the army — which has a camp nearby on New Alipore Road — to join hands with firefighters and police.

Several residents said they spotted the fire around 6.40pm and it gradually spread from one home to another.

Till late evening, over a dozen fire tenders were at work trying to control the fire. There were no reports of injuries, police said.

“It’s difficult to say how many houses were gutted because these are illegal structures that have come up on railway land adjoining the tracks,” said Calcutta’s mayor Firhad Hakim.

He was on the spot with Aroop Biswas, the state power minister, and Jui Biswas, the local councillor.

Another fire, off EM Bypass in Topisa, destroyed over 100 homes on Friday afternoon.

Sujit Bose, the fire services minister, reached the area later and so did Debasish Kumar, the MLA from Rashbehari.

“We don’t know what to do next. Our beds, tables and even cash have been destroyed,” said one of the residents, standing outside his charred house.

Councillor Biswas said the Kolkata Municipal Corporation has no records of these shanties because they are “illegal settlements”.