Images have emerged of 41 men trapped for more than a week in a highway tunnel in the Indian Himalayas, showing them standing in the confined space and communicating with rescue workers.

The men have been stuck in the 4.5km tunnel in Uttarakhand state since it caved in on 12 November and are safe, authorities said, with access to light, oxygen, food, water and medicines.

They have not said what caused the cave-in but the region is prone to landslides, earthquakes and floods. Efforts to bring out the 41 men have been slowed by difficulties in drilling through the debris in the mountainous terrain.

A 30-second video provided by authorities showed about a dozen of the trapped men standing in a semi-circle in front of the camera, wearing helmets and construction worker jackets over their clothes against the backdrop of the lights in the tunnel.