Chief Minister Mamata Banerjee told PTI that efforts were under way to trace at least two people who were reportedly trapped under the debris.
An eyewitness claimed that some people in a minibus and private cars were trapped. However, in a statement, KoPT said, "KoPT does not have any records of Majherhat Bridge been built by Kolkata port". Initially six fire tenders were pressed into service.
The fire brigade and disaster management group personnel were pressed in the rescue operations. The rescue operation was impeded due to occasional rain in the evening and lack of daylight on a rainy day. "It is a serious negligence and strict action will be taken", said Banerjee.
Police confirmed at least one death but local media reports five have been killed - and the death toll is expected to rise. We need to find out what went wrong in this case. But there is no flight available now.More news: Airstrike near United States base in southeastern Syria kills 8 pro-Assad fighters
Banerjee said she will visit the site on Wednesday cutting short her tour.
"Ten people have been rescued until now".
The Majerhat bridge in the crowded Alipore area caved in around 4.45 pm during rush hour.
Local railway services were affected as the bridge crossed a set of tracks.
Prime Minister Narendra Modi termed the incident "deeply unfortunate" and hoped for the speedy recovery of the injured. My thoughts are with the families of the victims. "I pray that those who are injured recover at the earliest", he wrote on Twitter.More news: Colin Kaepernick Is The Powerful New Face Of Nike's Latest Ad Campaign
West Bengal Governor K.N. Tripathi, who visited the accident site, said the maintenance of the bridge rested jointly with the State PWD and Railways and that the "matter needs to be inquired into".
Another minister Firhad Hakim said there has been no casualty in the incident, adding that all those trapped under the debris have been rescued, and six injured have been admitted to the nearby hospital.
"They have not found any trapped persons". The bridge runs over the Majerhat Railway Station and connects the city centre to Behala and other southern suburbs.
On March 3, 2013, a curved section of a flyover at Ultadanga in Kolkata connecting VIP Road and E M Bypass collapsed when a goods truck was passing.
The area near the site had been dug up for a metro railway project and construction materials are strewn all over the place.More news: New Pakistan PM to Skip UN General Assembly to Focus on Economy