DEHRADUN, India, Nov 13, 2023 (BSS/AFP) - Rescue workers in India used heavy excavators Monday to clear piles of debris in desperate efforts to reach 40 men, a day after the road tunnel they were building collapsed.

There were "some signals" the workers were alive, officials in the northern Himalayan state of Uttarakhand said.

Rescuers had been pumping oxygen into the blocked portion of the tunnel, and had managed to send food in through a water pipe.

"Some small food packets were sent in through a pipe which is also taking oxygen inside," rescue official Durgesh Rathodi told AFP from the site.

"We have received some signals back that the trapped workers are alive."

Rathodi said excavators had removed about 20 meters (65 feet) of heavy debris, but the men were 40 metres beyond that point.

Disaster response official Devendra Patwal said he believed the men were likely alive.

"The good thing is that the labourers are not crammed in, and have a buffer of around 400 metres to walk and breathe," Patwal told the Indian Express newspaper.

The 4.5-kilometre (2.7-mile) tunnel is being constructed between Silkyara and Dandalgaon to connect two of the holiest Hindu shrines of Uttarkashi and Yamnotri.

Photographs released by the government rescue teams showed huge piles of concrete blocking the wide tunnel, with twisted metal bars on its broken roof poking down in front of the rubble.

The tunnel is part of Prime Minister Narendra Modi's Char Dham Road Project, which is meant to improve connectivity for some of the most popular Hindu shrines in the country, as well as areas bordering China.

Accidents on large infrastructure construction sites are common in India.

In January, at least 200 people were killed in flash floods in ecologically fragile Uttarakhand in a disaster that experts partly blamed on excessive development.