UN Secretary General Ban Ki-Moon on Monday urged some soul-searching by Japan over its past, calling renewed rows with China and South Korea over Tokyo's modern imperial-era history "very regrettable."
Tokyo's relations with its neighbours have felt regular strains due to the legacy of Japan's wartime aggression, as well as territorial disputes.
"I find it very regrettable that the tension (among the three northeast Asian countries) continues on due to issues of history and other political reasons," Ban told reporters during his visit to Seoul this week.
"We need determination by political leaders. Correct awareness about history is needed," said Ban -- a former South Korean foreign minister.
Tokyo's political leaders should indulge in some "very deep introspection" Ban said, especially with regard to moves in Japan to revise its pacifist constitution.
The latest bout of regional tension was sparked by the visit this month of Japanese ministers and politicians to a controversial shrine in Tokyo that honours the World War II dead, including known war criminals.
The shrine is seen as a symbol of Tokyo's aggressive imperial past by China and South Korea, both of which reacted angrily to the visits.