Police in eastern Switzerland say five people died and 40 others were injured when a Dutch tour bus hit a roadside crash barrier and overturned on Thursday afternoon.

The bus overturned between the villages of Susch and Zernez in the Alpine canton of Graubuenden. The report said the bus had 45 people on board, while its summary referred to 48 passengers. Three people remained in serious condition at a hospital.

Prosecutors and police were investigating what led to the accident. No other vehicles were believed to be involved, police said.

The travel agency behind the trip, Oad, said in a statement that it was “deeply shocked and devastated by the tragic bus accident” and that its thoughts were with those involved and their loved ones.

Swiss President Guy Parmelin also wrote on X about the crash.