Several people have died and others were injured when a tourist coach carrying 48 passengers overturned on a mountain road in the eastern Swiss canton of Graubunden, local authorities confirmed Thursday evening.

The incident occurred around 8 p.m. local time when the coach flipped onto its side on an embankment next to the carriageway. Emergency services and helicopters responded to the scene. The cantonal police confirmed fatalities but did not immediately release the number of victims or their nationalities, stating that families were being informed.

The Dutch Federation of Travel Agencies (ANVR) identified the coach as belonging to Oad, a Dutch tour company, and confirmed all 48 passengers were from the Netherlands. According to the ANVR, the coach had departed the Netherlands on Monday and was on a day trip from Austria to Switzerland when the crash occurred.

The road where the accident took place connects the villages of Susch and Zernez. Zernez serves as an entry point to the Swiss National Park.

An investigation into the cause of the crash has been launched by the police.