It was too early to determine what caused the accident outside the town of Granges-pres-Marnand, Reto Schaerli, a spokesman for the national rail company SBB, said by phone.

The crash between two trains traveling to and from Lausanne on the same track occurred at 6:46 p.m., police for the Canton of Vaud said in a statement. The five severely injured were transported to hospitals in Lausanne and Payerne, police said. Newspapers including 20 Minutes earlier reported 44 injured.

The first news photos from the crash showed the fronts of both trains completely smashed into each other. An unidentified passenger on the train traveling to Lausanne told 20 Minutes that the train braked three times before a violent crash sent smashing glass flying through the cars. One of the engine drivers remains missing, with rescuers unable to get into the control cabin, police said.

The accident is the latest of several fatal train collisions in Europe. A crash in northern Spain after a high- speed train went off the rails on July 24 killed 79 people. On July 12, six people died when a French train smashed into a commuter station outside Paris.

Investigators from the rail service and specialists from the police and the Swiss federal accident investigative unit have opened a probe into the accident, police said.