A Swiss military helicopter scanned the Alps last night in the canton of Appenzell Inner Rhodes with a thermal imaging camera, searching for a hiker missing since Sunday.

The search did not yield a trace of the 33-year-old woman.

Ground crews and teams of search dogs have also not found the woman.

On Sunday afternoon the hiker used her mobile phone, telling rescuers she was injured in the Alpstein area.

Police said the hiker did not know exactly where she was, and efforts to trace the phone’s location have been unsuccessful.