TOKYO, September 24. /ITAR-TASS/. The Japanese Foreign Ministry has informed the Russian embassy it has taken note of Wednesday’s trip by the chief of the Russian presidential staff, Sergey Ivanov, to the South Kuril island of Iturup, a source at the Russian embassy in Japan has told ITAR-TASS.

“We have had a corresponding conversation at the Japanese Foreign Ministry,” the source said, adding that no official protest was expressed.

Earlier, the Cabinet’s chief secretary Yoshihide Suga expressed “extreme regret” over Ivanov’s visit to the Iturup island, but at the same time added it would not affect Moscow’s and Tokyo’s intention to continue their dialogue for the sake of advancing bilateral relations.

Ivanov arrived at Iturup earlier on Wednesday to inspect the newly-built airport and other facilities.

Japan claims that such visits are expected to assert Russia’s sovereignty over the islands, which Tokyo regards as its “Northern Territories. The four islands - Iturup, Kunashir, Shikotan and Habomai - are the subject of a 60-year-old dispute between the two nations.