Japan has summoned South Korea's ambassador to Tokyo after South Korean President Lee Myung-Bak visited a group of disputed islands that lie between the two countries.

Before Mr. Lee landed on the islands Friday, Tokyo officials had urged Seoul to call off the visit. Japanese Cabinet Secretary Osamu Fujimura said the action could impact South Korean-Japanese relations.

“If it's true, that would run counter to Japan's stance on Takeshima and it would be extremely regrettable. We strongly urge South Korea to call off this visit.”

It is the first ever visit by a South Korean president to the islands, known in Japan as Takeshima and in Korea as Dokdo. The islets have been under effective South Korean control since the end of Japanese colonial rule after World War II.

Last week, South Korea summoned a Japanese diplomat after Japan renewed its claim to the islands in its annual defense report.