AMSTERDAM (AP) — Japan’s Prime Minister Shinzo Abe paid a visit to the Anne Frank House museum in Amsterdam Sunday, a diplomatic move ahead of a meeting with the leaders of the US and South Korea to discuss North Korea.

Abe said it was “regrettable, quite regrettable” that 300 copies of Anne Frank’s diary were vandalized recently in Tokyo libraries. A suspect has been arrested and confessed.

“The suspect is currently under custody, and authorities are looking at his motivation, although we are not quite sure what his real motivation was,” he said in a press conference at the museum.

In the run-up to the Nuclear Security Summit in The Hague, Abe has sought to undo fallout from his December visit to Yasukuni Shrine, which honors all Japanese military casualties — including war criminals. The move angered China and South Korea and revived concerns about Abe’s nationalist and revisionist tendencies.

Earlier this month Abe said he won’t undo Japan’s past apologies for its actions in World War II.

Sunday, he said that the 20th century had been one of war and violations of human rights, such as what Frank suffered.

“Looking ahead of the remaining years of the 21st century, I would like to ensure that we will never see the same things happening during the years coming ahead,” he said. “And also I do share the responsibility to realize this goal.”

Frank, a Jewish teenager, spent two years in hiding from the Nazis in a small hidden apartment in Amsterdam during World War II. Her family was caught and deported, and she died at the Bergen Belsen concentration camp in 1945. The diary she kept was published after the war and has become the best-read document to emerge from the Holocaust.

Copyright 2014 The Associated Press.