U.S. Ambassador to Japan Caroline Kennedy on Thursday called on Japan and South Korea to mend their soured relations over a territorial dispute and different perceptions of history.

"I think that the two countries really should and will take a lead in this process, and the United States, being a close ally of both of them, is happy to help in any way that we can," Kennedy said in an interview aired by NHK.

Calling Japan and South Korea "the two closest Unites States allies in the region," Kennedy said "these good relations are in everyone's interest."

Prime Minister Shinzo Abe has not held formal talks with South Korean President Park Geun-hye since Park came to power in February 2013.

Japan and South Korea have been at odds over disputed islets that are controlled by South Korea but claimed by Japan as well as the issue of the "comfort women," who were forced to work at Japanese military brothels during the war.

Abe's visit in December to the war-linked Yasukuni Shrine as well as his indication for a possible rethink of the Japanese government statement on the wartime sex slavery issue has further exacerbated the relationship between Japan and South Korea.