At least 14 people were killed and dozens more injured when a flyover collapsed in a busy Indian city on Thursday, an official said, as emergency workers battled to rescue people trapped under the rubble.

At least 14 people were killed and dozens more injured when a flyover collapsed in a busy Indian city on Thursday, an official said, as emergency workers battled to rescue people trapped under the rubble.

The flyover was under construction when it collapsed onto a crowded street in the eastern city of Kolkata around lunchtime, crushing pedestrians, cars and other vehicles under concrete slabs and metal.

"Fourteen people are confirmed dead. More than 70 are injured," National Disaster Management Authority spokesman Anurag Gupta told AFP by phone.

"The rescue operation is still on as many people are trapped under the debris."

Police and pedestrians initially used their hands to try to move fallen girders and steel rods to reach people. An AFP reporter saw body parts in the debris.

Soldiers then rushed to the site, television footage showed, as locals armed with bamboo sticks raced to lift rubble and crowds gathered in the hope of hearing news of loved ones feared trapped.

"Everything is finished," screamed Parbati Mondal, whose fruit-seller husband was missing in the collapse.

Specialist rescue teams armed with concrete cutters, drilling machines, sensors to detect life and sniffer dogs were also on their way, Gupta said.

Kolkata, in India's east, is the venue of this Sunday's World T20 cricket final which is set to draw thousands of fans to the city.