TOKYO, April 19 (Xinhua) -- Two Japan Coast Guard (JCG) maritime survey vessels left port in Sakaiminato, Tottori Prefecture, on the Sea of Japan coast on Wednesday afternoon, and seemed to be ready to begin their work anytime ordered around a group of disputed isles in the Sea of Japan, arousing fierce opposition and warning from South Korea.

    The area to be surveyed lies within Japan's exclusive economic zone (EEZ), but also includes an area claimed by South Korea as its EEZ, as the two countries have not clearly set their EEZ border, Kyodo News reported.

    The two vessels, whose assignment is to create a hydrographic map of the survey area, seems to be still cruising aimlessly later in the day, local media said.

    Japan had initially planned to launch the survey as early as Thursday and conclude it on April 26, but will possibly delay it in response to the South Korean protests, Kyodo said.

    The Japanese government says the intended survey comes in response to South Korea's move to propose naming the seafloor topography of the area in question during an upcoming international conference in June.

    Japanese Chief Cabinet Secretary Shinzo Abe called on South Korea on Wednesday to "understand" its planned maritime survey, and insisted Japan's intends to go ahead with the work.

    "There is no problem in terms of international law that we conduct a scientific maritime survey within our country's exclusive economic zone," Abe was quoted as saying at a press conference.

    He said Japan is going to continue advancing the work without making a fuss in accordance with international law, and expect that the survey will be conducted peacefully of both sides dealing with it in a "level-headed" manner.

    However, Abe declined to disclose whether the JCG has dispatched ships for the survey and refused to comment on the present situation, but confirmed that preparations for it are under way.

    Meanwhile according to reports reaching here, South Korean demands that Tokyo immediately retract the planned survey.

    "If Japan goes ahead with the survey in South Korea's exclusive economic zone, the (South Korean) government will sternly deal (with the matter) in accordance with international law and domestic laws," Kyodo News quoted South Korean Foreign Affairs and Trade Minister Ban Ki Moon as saying after a security policy meeting convened by President Roh Moo Hyun.

    Kyodo said South Korean coast guard deployed more than 18 ships, including patrol vessels, around the South Korean-controlled islets, called Dokdo in South Korea and Takeshima in Japan, to block Japanese survey ships. Enditem