At least 17 workers died on Wednesday and several others were injured when a portal bridge collapsed on a railway bridge under construction in northeastern India, police said.

The collapsed structure was in Sairang, a town on the outskirts of Aizawal, the capital of Mizoram state, police said. The bridge had been under construction for about two years.

Residents nearby rescued the injured workers and took them to a hospital, authorities added. Rescuers from the National Disaster Response Force also went to the area to search for possible survivors.

The railway authorities are investigating the cause of the collapse. There were 40 workers on the site at the time of the accident, police added.

India’s transportation infrastructure has long experienced safety issues that have sometimes led to major tragedies on highways and bridges.

In October last year, a century-old suspension bridge collapsed into a river in the western state of Gujarat. Hundreds of people fell into the water and at least 132 died in one of the worst accidents in the country in the last decade.