NEW DELHI - In India, the first images of 41 construction workers trapped in a tunnel in the northern state of Uttarakhand emerged on Tuesday as rescue teams established visual contact with them.

The workers were building the tunnel as part of an ambitious highway project in the Himalayan mountains when it partially collapsed on Nov. 12.

A video, released by state authorities, shows the men wearing their helmets and construction jackets and standing around the medical endoscopy camera that was sent through a 15-centimeter pipe pushed through the rubble on Monday.

An official asks the men to smile and wave. The workers can be seen responding to the instructions.

The insertion of the wider pipe is being seen as a breakthrough. It was used late Monday to give the first hot cooked meal of rice and lentils to the men, who so far had survived on dry supplies like nuts and roasted chickpeas sent through a narrower pipe. Officials said it will also be used to send other essentials such as medicines, mobile phones and chargers.

"We will bring you out safely; do not worry," rescuers can be heard reassuring the men on the video. An official is also heard telling them to present themselves before the camera one by one to confirm their identities.

'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.'

Family members of the trapped workers who have gathered at the rescue site told reporters they were reassured after seeing the images of their relatives. Earlier rescue teams had used radios to contact the men, who are all low-wage workers.

Efforts to extricate them entered the 10th day on Tuesday. Initial attempts to drive a 91-centimeter-wide steel pipe horizontally through which the men could squeeze out were suspended on Friday due to concerns that more debris could fall and complicate the rescue operation.

Rescue efforts have also been slowed by the breakdown of heavy machines that were drilling through the rock and debris to create an escape route.

Despite the challenges, an international tunnel expert, who has joined the operation, has expressed confidence that the men will be rescued as multiple options are being explored.

'We've got mission from the top, missions from the front, mission from the side. The men are coming home. We're just not sure which door they're going to use," Arnold Dix, the International Tunnelling and Underground Space Association president, told news agency ANI. "We're knocking on the top door. We're knocking on all these doors. Which one opens? Not sure.'

Currently, engineers are creating an access road to the top of the hill from where they plan to dig a vertical shaft to reach the workers. Authorities said they would also continue digging horizontally from the mouth of the tunnel toward the laborers.

The effort is complicated by the geology of the Himalayas, a young mountain chain that is prone to landslides. Officials are not putting any time frame to the operation and have said digging will have to be done slowly.

"It may look easy from the outside, but on-site we have to factor in the effects of the drilling vibrations on the fragile terrain," Anshu Manish Khalkho, director of state-run highway management company National Highways and Infrastructure Development Corporation Limited, told reporters on Friday.

The government said in a statement on Monday that it is committed to saving the lives of all workers. "We are keeping constant communication and making all efforts to keep up the morale of the workers."

Authorities have not said what caused the partial collapse of the under-construction tunnel, which is part of Prime Minister Narendra Modi's ambitious highway project to improve connectivity and access to important Hindu pilgrimage locations in Uttarakhand. The picturesque state is often called the "Land of the Gods" due to its many Hindu religious sites.