SEOUL — President Lee Myung Bak of South Korea flew to a set of islets locked in a territorial dispute with Japan on Friday, dismissing protests from Tokyo and making a trip that was bound to heighten diplomatic tensions between Washington’s two key Asian allies.
Japan called Lee’s visit ‘‘unacceptable’’ and recalled its ambassador from Seoul in protest, Prime Minister Yoshihiko Noda told reporters in Tokyo.
Adding drama to the historical hostility that Lee’s surprise trip magnified, the archrivals were set to clash in London on Friday for the Olympic bronze medal in soccer.
Although South Korean Cabinet ministers and national legislators had previously visited the barely inhabitable volcanic outcroppings in the sea between Korea and Japan, Lee was the first South Korean president to travel there to highlight his country’s territorial control.
A contingent of armed South Korean police officers have manned the islets, called Dokdo in Korea and Takeshima in Japan, since the 1950s.
An elderly fishing couple also lives there with government support.
With his popularity plummeting amid corruption scandals implicating his associates, Lee is badly in need of a boost to his political leverage. Opposition politicians were quick to accuse him of making the unprecedented presidential trip to tap South Koreans’ deep-seated nationalistic sentiments against Japan for gains in domestic politics.
Although Lee is banned by law from seeking reelection in the presidential election scheduled for December, his governing party feared being labeled ‘‘pro-Japanese’’ so much that it forced his government in June to postpone the signing of an agreement to share classified military data with Japan.
The dispute over the islets remains one of the most contentious issues left unresolved from Japan’s often brutal colonial rule of the Korean Peninsula from 1910 until its World War II defeat in 1945.
Lee traveled there by helicopter. He stayed 70 minutes on the main islet, sharing pizza and chicken with police guards, Yonhap said.
His trip came after Japan angered South Koreans by reconfirming its territorial claim to the islets in its defense white paper published last month.
Lee is scheduled to deliver his last major national speech as president on Aug. 15, which South Korea celebrates as a major national holiday observing Japan’s World War II
surrender and Korea’s liberation.