A small tourist plane crashed in Switzerland on Sunday, killing all the three people on board, police said.

Local police confirmed that the accident occurred on Sunday afternoon at the Sanetsch Pass in southwestern Swiss canton of Valais.

While the skies were clear at the time, there was some wind, but the real cause of the accident remains to be investigated, police said.

According to Swiss public television RTS, the plane, a Piper Warrior II HB PTL, is a training plane and was registered to the Seeland Aviation Club of Biel in canton Bern.