An under-construction flyover in Varanasi collapsed on Tuesday evening with at least 16 feared dead and as many as 50 are trapped under the debris.

A portion of the flyover near Varanasi's cantonment area railway station came down on several people - possibly labourers. As many as four vehicles and a mini bus were crushed under the debris as well. "I was 50 meters away from where a portion of the flyover came down. Everyone around the area panicked and began screaming," an eyewitness said.

Rescue operations began soon after the incident with at least three JCBs at the spot. A boundary wall next to the flyover was also demolished to allow bigger vehicles to assist in operations and three people were safely evacuated by 2000hrs.

Officials from local administration have reached the spot and are taking stock of the situation. "It is an unfortunate incident. All hospitals in the area are on alert. Any casualty would be attended to immediately," said Sidharth Nath Singh, Uttar Pradesh minister.