Hopes for the imminent rescue of 41 men trapped in a highway tunnel in the Indian Himalayas for nearly two weeks were foiled by a problem with the drilling equipment, an official said on Friday, but efforts to reach the workers should resume soon.

The men, low-wage construction workers, have been confined in the 4.5-km (3-mile) tunnel in Uttarakhand state since it caved in early on November 12. Authorities have said they are safe, with access to light, oxygen, food, water and medicines.

Attempts to pull them out by drilling through the debris of rock, stones and metal and pushing through an evacuation pipe have been slowed by snags.

Rescuers had hoped to finish the drilling late on Thursday but had to suspend it after the platform on which the auger drilling machine is fixed was damaged and needed to be repaired, Deepak Patil, who is heading the rescue operation, told Reuters.

The last 10 metres (33 ft) of the 60-metre (197 ft) debris pile is left to be drilled through and work will resume once the platform is ready, he said.

The collapsed tunnel is on the Char Dham pilgrimage route, one of the most ambitious projects of Prime Minister Narendra Modi's government.

It aims to link four key Hindu pilgrimage sites with 890 km (550 miles) of two-lane road, at a cost of $1.5 billion.

Following the collapse, the National Highways Authority of India will do a safety audit of 29 tunnels it is building, the government has said.