Zojoji Temple in central Tokyo appears to be the latest target of attack by vandals suspected of defacing shrines and temples across the country this month with an unidentified liquid, according to the police.

Police are investigating at least a dozen stains that were found throughout the temple, near Tokyo Tower, including on the bell and the Sangedatsumon wooden main gate, which was built in 1622 and is designated an Important Cultural Property.

A temple official found a liquid stain on the main gate early Tuesday evening and reported the incident to the police on Wednesday morning after another stain was found on a stone figure. The gate remains open at night to allow free entry to temple premises.

The stains were made by an oily liquid, the temple official said.

Similar stains have been found this month at various shrines and temples, including Meiji Shrine, a Shinto site in Tokyo with strong Imperial connections; Shimogamo Shrine in Kyoto, a UNESCO World Heritage site; and Kimpusenji temple in Nara, a national treasure. Shurijo Castle in Okinawa was found to have been similarly damaged.

In 2015 the police issued an arrest warrant for a Japanese man living in New York on suspicion of defacing a Chiba shrine with an oily liquid.

The man, who claims to be the founder of a religious body, was suspected of spreading the oily substance at Katori Shrine in Chiba Prefecture and may be linked to other cases of vandalism at shrines and temples nationwide.