In spite of Tokyo administration's repeated warnings not to approach the pack of Dokdo isles, as they are called in South Korea, or Takeshima in Japan, situated in the southern part of the East Sea or Sea of Japan, a 2,500 ton South Korean ship with a crew of around 20 people on board, left Busan on Sunday night for a maritime survey, announced a South Korean official on Monday quoted by Reuters. The ship is scheduled to investigate the water temperature, currents and salinity around the islands till middle of July.

The reason of this apparently scientific survey is actually economic: the isles are within a rich fishing ground which, according to the South Korean authorities and the country's gas company, is located in an area that contains fresh gas hydrate deposits that need to be exploited.

On the one hand, South Korea took on the scientific side of the explanation stating: "It is the basic right and prerogative of this country to conduct any scientific research within our exclusive economic zone area" knowing that it maintains police forces to control the area.

On the other hand, Japan advised prudence on the part of South Korea, reminding it that the control over this territory continues to be disputed. "We would like to call upon South Korea again to be prudent enough to exercise self-control", stated the spokesman of the Japanese government on Monday.

Moreover, Chief Cabinet Secretary Shinzo Abe released another warning declaring that Japan would seek the help of the United Nations: "If South Korea goes ahead with the survey as planned, we will deal with it appropriately under the United Nations Convention on the Law of the Sea and domestic laws" since "It is not acceptable to carry out a survey within our exclusive economic zone without prior notification".

Japan annexed the islands in 1905, yet South Korea's Coast Guard has been stationed there since 1954.