Around 50 people are stuck in cable cars high above the glaciers of Mont Blanc in the French Alps this evening after a helicopter rescue operation was suspended as night fell, officials said.

The cable cars got stuck at an altitude of 3,800 metres (12,468 feet), initially with 110 people on board, the prefect of the Haute-Savoie region - Georges-Francois Leclerc - told AFP.

Mr Leclerc did not say whether the tourists remaining in the cable cars would have to spend the entire night suspended up there

They connect Aiguille du Midi on the French side of the mountains with Pointe Helbronner on the Italian border.

The problem was caused by cables that got crossed for "unknown reasons" around 4pm local time (3pm Irish time) and the employees of the Mont-Blanc Company were unable to repair them, Mathieu Dechavanne, CEO of the company that manages the cable cars, told AFP.

A rescue operation, including three helicopters from Switzerland, France and Italy, will be undertaken "that will take some time but the weather is good", Mr Dechavanne said.

"We are in contact with the clients [in the cable cars]. They have water and some means of communication but are beginning to find it's taking a long time," he added.

The cable cars, which carry four passengers each, offer a panoramic view of Mont Blanc.