WARSAW, Poland — The bodies of five skiers have been found on a glacier above the Swiss resort town of Zermatt, authorities said Sunday, after two hikers reported seeing abandoned skis near the Rimpfischhorn, a 4,000-meter peak in the Valais Alps.

Valais cantonal police said Sunday the victims were located on the Adler Glacier following aerial and ground searches.

Formal identification of the victims is still underway, and their nationalities have not yet been released.

Authorities have opened an investigation into the circumstances of the accident. Weather conditions and avalanche activity in the region are being examined as part of the probe.