SEOUL, April 14 (Xinhua) -- The South Korean government warned Friday that it will take stern measures if Japan conducts maritime research in waters near the disputed islets located in the East Sea (Sea of Japan) without South Korea's approval.

    The warning was made in a press release by the South Korean Foreign Ministry after Japan's maritime authorities informed the International Hydrographic Organization (IHO) that Japan plans to conduct maritime research by a government-owned vessel in the waters near the South Korean-controlled islets of Dokdo, which is called Takeshima by Japan.

    "The waters in which Japan plans to conduct the research works include South Korea's EEZ (exclusive economic zone)," the ministry said in the press release following an emergency meeting of related ministries at the Presidential Office.

    It also urged Japan to receive Seoul's approval for such research according to the international law on EEZ, warning South Korea will take stern measures against any foreign vessel entering its waters without approval.

    South Korean Vice Foreign Minister Yu Myung-Hwan called Japanese Ambassador to Seoul Oshima Shotaro on Friday to express South Korea's stance on the issue and urged Japan to retract the research plan.

    The South Korean Yonhap News said Japan's research plan is scheduled from Friday till June 30, but it is still unknown when the research ship will set sail.

    Japan persistently claims sovereignty over Dokdo, which are controlled by South Korea.

    South Korea insists that the Dokdo islets, located some 89 kilometers southeast to South Korean Uleung Island and 160 kilometers northwest to Japanese Oki Island, has been listed as its territory in history literature since the fifth century.

    While Japan also claims the islets has been its territory since17 century, as written in literatures.

    Japan started annexation of the Korean Peninsula in early 20 century and completed it in 1910. After liberation from Japanese colonial rule in 1945, the first South Korean President Lee Seung-man issued a presidential declaration on the dominion over the coastal sea and sovereignty over Dokdo in January 1952. Enditem