The police said the helicopter, which was carrying six people, crashed on a mountain landing site while involved in a heli-skiing trip on Tuesday, reported German news agency (dpa). In addition to the pilot, a mountain guide and his four customers were on board the B3 helicopter.

Two of the injured were reportedly able to receive immediate medical treatment before being flown to a clinic. “A third person was also rescued later,” the police added.

The accident occurred on the Petit Combin mountain, which is around 3,600m high. The Swiss Transportation Safety Investigation Board has launched an investigation to determine the cause of the accident.