South Korean president Lee Myung-bak made a surprise visit today to islets at the centre of a long-running territorial dispute with Japan, ignoring warnings from Tokyo that it would worsen the neighbours' already strained relations.
Mr Lee made the trip to the rocky, largely uninhabited outcroppings in fish-rich waters with the governor of North Gyeongsang province, according to an official in the governor's office.
Before the trip, officials said a visit would make Mr Lee the first South Korean leader to travel to the islets.
Mr Lee also briefly visited nearby Ulleung Island, which is home to a large South Korean population and not part of the territorial dispute.
The visit to the islets, called Dokdo in Korean and Takeshima in Japanese, comes as Mr Lee's conservative party jockeys for votes ahead of hotly contested December presidential elections.
Mr Lee, whose popularity has steadily dropped, is in the last year of his five-year presidency and cannot run for re-election.
The trip also comes on the eve of the men's bronze medal Olympic football match between Japan and South Korea and days ahead of South Korea's commemoration on Wednesday of the peninsula's independence in 1945 from 35 years of Japanese colonial rule.
South Korea stations a small contingent of police officers on the disputed islets in a show of control, but Japan maintains that the rocks are its territory, renewing the claim last month in an annual defence report.
Japanese foreign minister Koichiro Gemba warned before the visit that it would have a "strong impact" on relations and urged Seoul to call it off.
The outcroppings have long been a source of discord, even though the two countries share vibrant trade and tourism ties and are both partners in diplomatic efforts to persuade North Korea to abandon its long-range missile and nuclear arms programmes.
Historical and territorial issues, however, plague the relationship. Many people on the Korean Peninsula continue to harbour deep resentment stemming from Tokyo's brutal colonisation.
South Korea and Japan also remain at odds over what many South Koreans say is Japan's failure to properly address its past actions, including Japan's Second World War use of Korean women as sexual slaves for its soldiers.
In late June, Seoul and Tokyo put on hold an intelligence sharing pact seen as a breakthrough in their relations after a political outcry in South Korea.
South Korean activists last year placed a statue of a girl representing victims of Japanese sexual slavery in front of the Japanese Embassy in Seoul.
Japanese officials have apologised in the past, but Tokyo has refused repeated demands from individuals for reparations, saying the matter was solved by international peace treaties.
Last year, Seoul banned three conservative Japanese lawmakers from entering South Korea after they arrived at a Seoul airport with announced plans to travel near the islets.