At least 18 workers, all of them hailing from Malda in Bengal, were killed after a part of an under-construction railway bridge collapsed in Mizoram on Wednesday, police said.

The incident occurred around 10am in Sairang, about 21km from the state capital, Aizawl. All the deceased were identified as workers from Bengal, an official in Aizawl said on Wednesday night.

A Northeast Frontier Railway official told The Telegraph that the mishap took place because of the collapse of a gantry (an overhead steel structure) that was being launched on the under-construction bridge over the Kurung river.

“The gantry collapsed when it was being launched to connect the two piers of the bridge. The gantry was 103.5 metres long while the tallest pier was 95 metres and the shortest 25 metres,” the official said.

Aizawl deputy commissioner Nazuk Kumar told this newspaper: “We have found 18 bodies. All of them from Malda. Three are injured. We are still searching and cannot put an exact number to those missing.” The search will resume on Thursday morning.

The official said that after post-mortem, all the 18 bodies were sent to Malda by road under RPF escort around 9pm. It will take 24-27 hours to reach Malda, she said.

Most of the victims are from Pukuria, English Bazar and Manikchak in Malda district, an official in Bengal said.

Till 5pm, 18 bodies had been recovered. The total length of the bridge is 362 metres and the project deadline was December this year.

The sources said three injured workers were receiving treatment at Aizawl Civil Hospital.

A high-level committee has been constituted to probe the incident involving the under-construction bridge, one of the 130 bridges in the Bhairavi-Sairang New Railway Line project.

Volunteers from nearby areas and Aizawl helped the NDRF, SDRF and the quick response team of the police in the search-and-rescue operation.

The under-construction railway bridge is part of the 51.8km Bairabi-Sairang broad-gauge project, the foundation of which was laid by Prime Minister Narendra Modi on November 29, 2014, to provide rail connectivity to the Mizoram capital.

The project is being executed by Braithwaite Burn And Jessop Construction Company Ltd (BBJ), a central government undertaking, and ABCI Infrastructures Pvt Ltd, the railway official said, adding that work on the affected bridge started two years ago.

Mizoram found its place on the country’s railway map with the commissioning of the 84km gauge conversion from Katahal in Assam’s Cachar district to Bairabi in Mizoram in May 2016.

On X (formerly Twitter), Bengal chief minister Mamata Banerjee expressed shock, adding that she had instructed the chief secretary to coordinate with the Mizoram administration for rescue and assistance. She promised due compensation as soon as possible to the affected families.

Prime Minister Narendra Modi, who is in South Africa, condoled the deaths on X and announced an ex gratia of Rs 2 lakh each for the next of kin of the workers who died and Rs 50,000 to the injured.

Additional reporting from PTI