The Auschwitz-Birkenau Museum condemned the spray-painted inscriptions, which were written in both English and German.
The museum said in a statement it was "an outrageous attack on the symbol of one of the greatest tragedies in human history and an extremely painful blow to the memory of all the victims of the German Nazi Auschwitz-Birkenau camp."
Police make appeal for possible witnesses to come forward
The graffiti included "two references to the Old Testament, often used by antisemites and denial slogans," the museum added.
Police are analyzing and compiling evidence as well as reviewing video surveillance of the incident. Investigators have also appealed for any witnesses, who may have information or evidence, to come forward and assist with the investigation.
The museum said once this procedure has concluded, it would then remove the offensive graffiti.
More than 1.1 million people — most of them Jews — perished in gas chambers at the camp or from starvation,
cold and disease in the period it was operational from 1940 to 1945.
The camp was set up on Polish soil by Nazi Germany during World War II.
kb/jsi (AFP, KNA, Reuters)