Firefighters battled for hours to contain a blaze ​that engulfed the former Nazi guest house ‌known as "The Eagle's Nest" in southern Germany, while police investigated the cause after detaining a man near the ​scene, authorities said on Saturday.

Around 200 ​firefighters and emergency workers near Berchtesgaden in Bavaria were ⁠battling the flames after the building, known ​as the Kehlsteinhaus, caught fire on Friday, police ​said.

Built in 1938 as a guest house for Nazi officials and their guests, the building sits in a spectacular Alpine ​setting above Berchtesgaden. Adolf Hitler used it occasionally, earning it ​the nickname "Hitler's Tea House". It is separate from his ‌nearby ⁠summer residence, the Berghof.

Bild newspaper quoted a police spokesperson as saying the building, preserved after World War Two as a historical monument linked to the Nazi era, had ​been so ​badly damaged ⁠that it "could probably not be saved".

Police said earlier they had detained ​a man near the site but ​had ⁠not yet established the cause of the fire.

"Whether the person is linked to the fire ⁠is ​currently the subject of a ​criminal investigation," Bavarian police said in a statement.