LUCKNOW, India (AP) — Rescuers are working around the clock Tuesday to remove debris to extract 40 workers who have been trapped for over two days after an under-construction tunnel collapsed in northern India. Officials hope to extricate them in the next 24 hours.

A 2.5-foot (0.76 meter)-wide steel pipe will be pushed through an opening of excavated debris with the help of hydraulic jacks to safely pull out the stranded workers, authorities said.

About 200 rescuers from federal and state disaster relief agencies are using drilling equipment and excavators to reach them.

The tunnel collapsed Sunday in Uttarakhand, a mountainous state dotted with Hindu temples that attract many pilgrims and tourists. The tunnel is part of the busy Chardham all-weather road, a flagship federal government project connecting various Hindu pilgrimage sites.

Senior government official Ranjit Sinha said falling debris has been hindering the rescue operation and added they expect to free the workers by Tuesday night or Wednesday. He said all the workers were alive and that they supplied them with water and dry food through a pipeline

Families of the trapped workers are worried and have been following the rescue process closely.

Lakshmi Pakhirai, mother of one of the workers said, “someone who is there in Uttarakhand called and told us that Souvik is fine and rescue workers have spoken to him. They said he is fine and healthy.”

The collapsed portion of the 4.5-kilometer (2.7-mile) tunnel is about 200 meters (500 feet) from the entrance, Karamveer Singh, an official with the National Disaster Response Force, said.

Singh said rescuers had also established contact with the stranded workers using walkie-talkies, and in one case a written message on paper was sent through the pipeline to communicate with them.

Sinha, the government official, said the tunnel collapsed due to a landslide.

Most of the workers stuck inside were migrant laborers from across the country.

Uttarakhand sees a huge flow of pilgrims and tourists every year to visit the temples, with the numbers expanding over the years due to the continuous construction of buildings and roadways.

In January, state authorities moved hundreds of people to temporary shelters after a temple collapsed and cracks appeared in over 600 houses because of the sinking of land in and around Joshimath town in the region.