SUSCH, Switzerland — A tour coach carrying 48 Dutch passengers overturned on a mountain road in Graubunden canton on Thursday evening, killing several people and injuring others, local authorities said.

The crash occurred at 8 p.m. on a road connecting Susch and Zernez in the Engadine valley. Cantonal police said they had not yet disclosed the specific death toll or identities, citing a need to inform families before releasing details publicly.

The coach was operated by Oad, a Dutch tour company, according to the Dutch Federation of Travel Agencies (ANVR). All 48 passengers were from the Netherlands. The vehicle had departed the Netherlands on Monday and was returning from Austria when it crashed.

Emergency services rushed to the scene, with helicopters landing near the site as rescue teams worked around the overturned coach, which came to rest on an embankment alongside the road.

Police have opened an investigation into what caused the coach to leave the road.