South Korea will send back a letter that Prime Minister Yoshihiko Noda wrote to President Lee Myung Bak in which he described as regrettable Lee's recent visit to disputed islets in the Sea of Japan as well as remarks he made regarding Emperor Akihito, a senior South Korean Foreign Ministry official said Wednesday.

"The news report is correct," the official said when asked by a reporter to confirm a report by a South Korean newspaper of the decision to return the letter to its sender.

In the letter, which was handed to a minister at the South Korean Embassy in Japan, Noda also informed Lee of Japan's plan to take the territorial dispute to the International Court of Justice, and urged South Korea to act, bearing in mind the future of Japan-South Korea ties.