Rescue teams in northern India delivered food and medical supplies to 40 construction workers on Thursday while authorities geared up to commence drilling through the debris to reach the individuals stranded since a segment of the tunnel they were working on collapsed over the weekend.

Rescuers planned to insert wide steel pipes to create a passage to free the workers trapped since early Sunday in the mountainous Uttarakhand state. A drilling machine was assembled after three Indian Air Force transport aircraft flew their parts from New Delhi on Wednesday.

The workers are being provided with cashew nuts, peanuts, soaked and roasted chickpeas, popcorn and medicines every two hours, said Devendra Patwal, a disaster management relief official.

Some complained of fever and body aches on Wednesday, but there has been no deterioration in their condition, he said.

Yogesh, who uses only one name, cut short his Diwali celebrations and rushed to the collapsed tunnel when he learned that his brother was trapped. He spoke to Vishal, his brother, on Wednesday.

"He sounded tense but said he was okay. He asked about the rescue operation, and I told him that it is going on a war footing," said Yogesh.

Anshu Manish Khalko, a National Highways and Infrastructure Development Corporation official, said he expected the drilling operation to start sometime Thursday.

"Once operational, this machine will facilitate the creation of an escape tunnel quickly to ensure evacuation of the trapped laborers," he said.

On Wednesday, relatives and friends of the trapped workers gathered outside the tunnel and were seen growing frustrated and angry. The state government has been consulting with the Indian army and foreign experts on ways to proceed with the rescue.

State officials have contacted Thai experts who helped rescue a junior association football team trapped in a cave system in northern Thailand in 2018, state government administrator Gaurav Singh said. They have also approached the Norwegian Geotechnical Institute for possible help, Singh said.

About 200 disaster relief personnel have been at the site using drilling equipment and excavators in the rescue operation, with the plan to push 75-centimeter-wide (2.5-foot-wide) steel pipes through an opening of excavated debris.

Falling debris lightly injured two rescue workers and delayed operations on Tuesday and Wednesday. No fresh landslide has occurred since Tuesday.

A landslide during road construction caused a portion of the 4.5-kilometer (2.7-mile) tunnel to collapse about 200 meters (500 feet) from the entrance. It is a hilly tract of land, prone to landslide and subsidence.

Uttarakhand is a mountainous state dotted with Hindu temples that attract many pilgrims and tourists, and the construction of highways and buildings has been constant to accommodate the influx.

The tunnel is part of the busy Chardham all-weather road, a flagship federal project connecting various Hindu pilgrimage sites.