BERLIN (AP) — Dozens of exhibits at prominent museums in Berlin have been sprayed with an oily liquid, according to German media reports. Police said Wednesday that an investigation is ongoing, but wouldn't comment further.

The weekly Die Zeit and Deutschlandfunk radio reported Tuesday night that at least 70 objects at the Museum Island complex, a UNESCO world heritage site in the heart of the German capital that is one of the city's main tourist attractions, were sprayed on Oct. 3, the 30th anniversary of German reunification.

They said that exhibits at the Pergamon Museum, Alte Nationalgalerie, Neues Museum and other sites were affected. It wasn't clear who might have been responsible.

Visible stains were left on Egyptian sarcophagi, on sculptures and 19th-century paintings, according to the report. Berlin police would say only that an investigation is ongoing, but wouldn't comment on details of what happened. Officials at the Prussian Cultural Heritage Foundation, which oversees the museums, couldn't immediately be reached for comment.