Stumbling stones for Holocaust urvivors Siegfried and Edith Robinski in Berlin. Picture: The Conversation

Berlin - Police in Berlin were investigating the theft of several small memorials embedded in sidewalks that pay tribute to victims of the Holocaust.

Residents of the central Berlin district of Neukoelln alerted police to the crime on Monday, with several streets affected. No clues have yet been identified to help nail the alleged thieves.

The gold-coloured, cobblestone-sized monuments called "stolpersteine" (or stumbling stones) are laid into the pavement in front of the last known residence of a Nazi victim.

The name, birth date and fate of the person (where such information is available) is inscribed on the block, which sits just above the regular street level. More than 60 000 of the memorials can be found across Germany and Europe. Many descendants of Holocaust victims visit the stones to honour their relatives. 

Nazi Germany murdered 6 million Jews during the Holocaust, along with homosexuals, Roma gypsies, disabled people, political opponents and other "dissidents".