At least 12 people were killed and an as yet undetermined number injured or missing after a tunnel they were digging collapsed in the northern Indian state of Uttaranchal, police said Tuesday.
A senior police official said a survivor had told him about 75 to 80 people were in the tunnel when it started to collapse late Monday.
Fifty had been rescued or managed to come out on their own by late evening, three of whom were seriously injured, he said.
Police overnight pulled out the bodies of nine workers, while three others were retrieved Tuesday, the official added.
The death toll could rise as high as 25, an official from the company digging the tunnel, told AFP.
The tunnel is part of a controversial hydro-electric power project which environmentalists say is dangerous as it is being built in an earthquake prone region.
Local district official Puneet Kansal told Aaj Tak television news channel that labourers were working in the tunnel when earth started falling from the roof.