The U.S. Congressional Research Service has noted that Prime Minister Shinzo Abe's comments and actions on historical issues "have raised concern that Tokyo could upset regional relations in ways that hurt U.S. interests."
In a report dated May 1, the research arm of Congress said Abe is known as a "strong nationalist" and that his approach to issues relating to wartime sex slaves, history textbooks and visits to war-linked Yasukuni Shrine "will be closely monitored" not just by China and South Korea but also by the United States.
Japan's ties with China and South Korea, already strained by territorial disputes, have worsened as a result of comments by Abe that appear to gloss over Japan's aggression during World War II. One comment suggested that the word "aggression" is defined differently from country to country.