Anne Frank's "The Diary of a Young Girl" and scores of books about the young Holocaust victim have been vandalized in Tokyo public libraries since earlier this year, according to the Associated Press.
The damage was mostly in the form of dozens of ripped pages in the books, the AP reported.
Until now, librarians have counted at least 265 damaged books at 31 municipal libraries since the end of January, according to the AP.
Japan and Nazi Germany were allies in World War II, and though Holocaust denial has occurred in Japan at times, the motive for damaging the Anne Frank books is unclear and police are investigating, the AP reported.
Chief Cabinet Secretary Yoshihide Suga called the vandalism "shameful" and said Japan would not tolerate such acts, according to the AP.
In the Nakano district libraries, the vandals apparently damaged the books while unnoticed inside reading rooms, according to city official Mitsujiro Ikeda, the AP reported.
"Books related to Ms. Anne Frank are clearly targeted, and it's happening across Tokyo," Ikeda said Friday, according to the AP, adding that "It's outrageous."
At another library, all the books that were damaged could have been found using the keywords "Anne Frank" in an online database, the AP reported.
One of the libraries involved in the attack against Frank-related books has moved them behind the counter for protection, but they can still be checked out, according to the AP.
Anne Frank wrote her diary over the two years she and her family hid in a concealed apartment in Nazi-occupied Netherlands during World War II, the AP reported. After her family was betrayed and deported, she died in a German concentration camp at age 15 in 1945.
Her diary has become the most widely read document to emerge from the Holocaust after her father survived the camps and published it, according to the AP.
The Simon Wiesenthal Center, a U.S.-based Jewish human rights organization, issued a statement calling the vandalism a hate campaign and urging authorities to step up efforts to find those responsible, the AP reported.
