Four Germans were arrested leaving white roses in memory of Adolf Hitler at the house where he was born in western Austria on the anniversary of his birth.
They are two sisters and their partners, all aged 20 and 30, who went to the building on Saturday to place white roses in the windows.
One woman even paid a salute to Hitler as they posed for photographs, authorities said.
Patrolling police officers spotted the group and took the young men to a police station for questioning.
Reuters: Ukraine abruptly withdrew from an imminent agreement with Russia in the Black Sea
The woman said she did not mean the salute, but officers said they found a conversation on her mobile phone with the others in which they were sharing messages and photos with Nazi content.
All four will be charged with violating an Austrian law banning symbols of Nazism.
Hitler was born on 20 April 1889 in Braunschweig am Inn. After a long-running dispute over the future of the house where he was born, work began last year to convert it into a police station to make it unattractive as a place of pilgrimage for neo-Nazis.