Part of a wrought-iron gate bearing the Nazis' slogan "Arbeit macht frei," or "Work sets you free," has been stolen from the former Dachau concentration camp, police said Sunday.

Dachau, near Munich, was the first concentration camp set up by the Nazis in 1933. More than 200,000 people from across Europe were held there and over 40,000 prisoners died before it was liberated by U.S. forces on April 29, 1945. The camp is now a memorial.

Memorial director Dr. Gabriele Hammermann condemned the theft of the gate, which she described as "the central symbol for the prisoners' ordeal."

Security officials noticed early Sunday morning that the gate section measuring 190 by 95 centimeters (75 by 37 inches) was missing, police said in a statement. Whoever stole it during the night would have had to climb over another gate to reach it, they added.

Police found nothing in the immediate vicinity of the camp and appealed for anyone who noticed any suspicious people to come forward. The thieves, they said, probably transported the stolen gate with a truck or a car.

Speaking with Haaretz, Dr. Hammermann called the theft "the heaviest attack on the memorial site" yet.

According to Hammermann, officials at the private security service that supervises the site had decided against surveillance of the former camp with video cameras because they didn't want to turn it into a "maximum-security unit." That decision may now have to be reviewed, she added