Forty-one Indian workers trapped in a collapsed road tunnel for 10 days were seen alive on camera for the first time Tuesday as workers attempted to create new passageways to free them.

One of the proposed routes is nearly half a kilometer long.

Looking exhausted and anxious, with thick beards, the men could be seen peering at the endoscopic camera sent by rescuers down the thin pipe through which air, food and water are being sent.

"We will bring you out safely, do not worry," rescuers can be heard telling the helmet-wearing men trapped inside as they gather near the camera, video released by state authorities shows.

Excavators have been removing tons of earth, concrete and rubble from the under-construction tunnel in the northern Himalayan state of Uttarakhand since 12 November, after a portion of the tunnel collapsed.

But rescue efforts have been slow, complicated by falling debris as well as repeated breakdowns of crucial heavy drilling machines, with the air force having to twice airlift in new kit.

'Top priority'

Before the camera was introduced, rescuers had been communicating with the men inside using radios.

"All the workers are completely safe," Uttarakhand chief minister Pushkar Singh Dhami said in a statement. "We are trying with all our might to get them out safely soon."

Dhami said he had spoken to Prime Minister Narendra Modi about the men, adding Modi told him it had to be their "top priority" to get the workers out.

Engineers had been trying to horizontally drive a steel pipe just wide enough for the increasingly desperate men through at least 57 meters of earth and rock that block their escape.

But the giant earth-boring machine they were using ran into boulders it could not get through.

Drilling on that route was paused on Friday after a cracking sound created a "panic situation," officials said.