BERLIN — Berlin police confirmed Wednesday that they are investigating the vandalism of dozens of antiquities in three of the capital's museums this month.

About 70 artifacts were visibly damaged at the Pergamon Museum, Alte Nationalgalerie and Neues Museum, police said. All three are on Berlin's Museum Island, a UNESCO World Heritage Site in the Spree River that courses through the city.

The German news outlets Die Zeit and Deutschlandfunk, which first reported the damage, said that Egyptian sarcophagi were among the items visibly marked with an oily substance. Museum representatives said none of the museums' most famous exhibits — which include a renowned bust of Egyptian Queen Nefertiti — were affected.

Carsten Pfohl, the criminal director at the State Criminal Police Office, said police have not been able to identify the perpetrator or perpetrators on security video footage. He said he would not "engage in speculation" about a motive. Investigators have looked for links among the objects that were damaged but have not found any, he said.

German media have noted that the Pergamon Museum has become a target for conspiracy theorists in recent months. QAnon, a theory that falsely alleges that a cabal of Satan-worshiping pedophiles is running a global child sex-trafficking ring and battling to bring down President Trump, has gained new followers in Germany during the coronavirus pandemic.

Attila Hildmann, a vegan chef who has become prominent during anti-lockdown protests in Germany spouting baseless theories on topics such as forced vaccines and Microsoft founder Bill Gates, is one of QAnon's most vocal proponents in Germany, and he has also taken aim at the Pergamon Museum.

He has described the museum's Pergamon Altar, a 2nd-century B.C. artifact built in ancient Greece during the reign of King Eumenes II, as the throne of Satan and a site for child sacrifice. It is undergoing a long refurbishment and is not displayed to visitors.

Hildmann called on his followers to storm the museum in August, according to German news reports.

Christina Haak, the deputy director general of state museums in Berlin, said several acts of vandalism occurred outside the museums over the summer, with posters cut up and graffiti sprayed. However, she said, the latest attacks on dozens of exhibits amounted to the worst vandalism at the city's museums.

"The vandalism shocked us," she said, adding that 63 exhibits were soiled, three or four of which were on loan. It was not immediately possible to put a price on the damage, she said.

The Pergamon Museum also houses the blue-tiled Ishtar Gate, which once marked the entrance to the city of Babylon in what is now Iraq. The Alte Nationalgalerie, or Old National Gallery, opened in the late 19th century to house what at the time was considered contemporary art. Museum representatives said that no paintings were damaged but that some frames were.

Berlin's Neues Museum, which largely houses ancient Egyptian artifacts, is home to the famed Nefertiti bust. It was on display as usual Tuesday, with little outward sign of extra security.