Rescue workers were working to see if anyone was trapped in the debris after a bridge collapsed on Tuesday (local time) in the eastern Indian city of Kolkata, government officials said.
Cars were seen among the rubble and a large portion of the bridge was destroyed, but as yet it was not known if there were casualties.
"We are trying to assess if there are people trapped beneath the debris," Sovan Chatterjee, the mayor of Kolkata, who visited the accident site, told Reuters.
Mamata Banerjee, chief minister of West Bengal state, said in a televised address: "We are still assessing the gravity of the situation and we cannot talk about the deaths right now."
All India Trinamool Congress, the West Bengal state's ruling party, said on Twitter the bridge was 40 years old.
There were no more immediate details of the cause of the collapse.
In March 2016, another bridge collapsed in the city, killing more than two dozen people.