A bus carrying up to 45 people plunged into a deep ravine near a Malaysian mountaintop tourist resort Wednesday, police said, but added they could not yet confirm any casualties.

The vehicle tumbled off a steep road near the Genting Highlands, a gambling and entertainment resort about an hour's drive from the capital Kuala Lumpur, police said.

"We believe the bus had about 40 to 45 people inside but we are not sure of their nationalities," a local police officer in the area told AFP by phone.

Police said the bus was part of a line that regularly ferries both tourists and locals between the capital and the hill resort.

Malaysian media said the accident occurred around 3pm.

Amateur photos circulated on the Internet shortly afterward, showing a bus lying on its side in thick vegetation about 100 feet downhill from the road.

Police said rescue efforts were underway, but could provide no further details.

The road to the Genting Highlands is notoriously steep and winding, and accidents are common.

Two Indian tourists died and 22 other people were hurt in March 2012 when their bus overturned in the area.