Rescuers are working around the clock to remove debris and extract 40 workers who have been trapped for more than two days after an under-construction tunnel collapsed in northern India.
Officials hope to extricate them in the next 24 hours.
A 2ft 6in wide (0.76m) steel pipe will be pushed through an opening of excavated debris with the aid 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 on 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 that they expect to free the workers by Tuesday night or Wednesday.
He said all the workers are alive and have been supplied with water and dry food through a pipeline.
Worried families of the trapped workers 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 2.7-mile (4.5km) tunnel is about 500ft (200m) from the entrance, Karamveer Singh, an official with the National Disaster Response Force, said.
He said rescuers have 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.
Government official Mr Sinha said the tunnel collapsed due to a landslide.
Most of the workers trapped inside are migrant labourers 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 roads.
In January, state authorities moved hundreds of people to temporary shelters after a temple collapsed and cracks appeared in more than 600 houses because of the sinking of land in and around Joshimath town in the region.
