Cable cars that were stuck overnight thousands of metres up among the glaciers of Mont Blanc with some 30 tourists on board were restarted on Friday, the operators said.

"It restarted five minutes ago, the last cable (which was blocking the system) was untangled," Mathieu Dechavanne, the head of the operating company said just before 8am (0600 GMT). The remaining passengers will be rescued without the use of helicopters.