GENEVA (AP) — A Dutch tour bus overturned in eastern Switzerland in a serious accident that left several people dead and others injured, police said.

The bus overturned between the villages of Susch and Zernez in the Alpine canton of Graubuenden, and rescue teams were responding to the scene, authorities said. The police did not specify the number of dead and injured.

According to Swiss media, 48 people were on the bus. A spokeswoman for ANVR, a Dutch travel industry association, told the Blick newspaper that the passengers were Dutch.

A police spokesman said that the coach collided with the crash barrier and then overturned. No other vehicles were believed to be involved.

Several ambulances and five helicopters were deployed to the location, according to Swiss media.