DPA - Anti-Semitic slogans were found scrawled on a section of the former Berlin Wall as the city hosts thousands of Jewish athletes taking part in the Maccabi Games, German police said Saturday.

The hate speech was written on the city's iconic East Side Gallery on a mural that depicted a painting of the Israeli flag superimposed over a German flag.

Police said the incident is being investigated and that the mural has been temporarily covered until the graffiti can be removed.

No details were given on the slogans, which were discovered on Friday.

Open gallery view Competitors walk at an entrance hall during the 14th European Maccabi Games at the Olympic park in Berlin, Germany July 29, 2015. Credit: Reuters

The East Side Gallery, the longest standing section of the Berlin Wall, is considered the world's largest outdoor gallery and a popular tourist attraction.

The monument features more than 100 original mural paintings by artists from all over the world, who came to leave their mark along the city's Spree river after the collapse of communist East Germany and the fall of the Berlin Wall in November 1989.

The painter of "Vaterland" and one of the gallery's original designers, Guenther Schaefer, told DPA he would paint over the hate speech on Saturday after assessing the extent of the damage.

Berlin stepped up security in the city after more than 2,000 athletes arrived for the Tuesday opening of the Maccabi Games, a Jewish sporting event first held in 1932 in response to the exclusion of Jewish athletes from sporting clubs in Europe.

Berlin's hosting of the event in the Nazi-era Olympic Park marks the first time the games are being held in Germany after the Holocaust in which some 6 million Jews died.

A group of Jewish teenagers wearing skullcaps were harassed with anti-Semitic remarks in the German capital on Friday, police said.