NEW DELHI, Dec. 30 (Xinhua) -- At least 35 people have been injured after a coal mine collapsed in the eastern Indian state of Jharkhand, a police official said Friday, adding that some 60 others are still feared trapped inside.

"The incident happened Thursday night when a large heap up of mud caved in inside the Rajmahal Open Cast Mines of Eastern Coalfields Limited in the state's Godda district. Nearly 40 vehicles were also inside the mine at the time of the mishap," he said, on condition of anonymity.

Rescue operations, which were severely hit by dense fog, began early this morning, and efforts are on to shift all the injured to a hospital, the official said, adding that no deaths have been reported in the incident so far.

Local TV channels reported, quoting mine officials, that mining operations were taking place about 61 meters beneath the ground when the mishap happened, and showed footage of the caved-in coal mine as rescuers try to get in amid dense fog.

India is the world's third largest coal producing nation and coal supplies 60 percent of the country's energy needs, but poor maintenance of the mines is a major factor behind frequent accidents.