Seventeen people, including three lawmakers from the main opposition Democratic Party, have landed on the islands in the Sea of Japan, which are also claimed by Tokyo.
As they set foot on the islands, called Takeshima in Japan and Dokdo in South Korea, on Tuesday, they criticized Japan for claiming sovereignty over the islands, which the party says are under South Korea’s effective control.
The Japanese Foreign Ministry lodged a protest with the South Korean side later in the day.
Hiroyuki Namazu, director general of the ministry’s Bureau of Asian and Oceanic Affairs, told Kim Jang-hyun, a senior official at the South Korean embassy in Tokyo, that the islands are clearly Japan’s inherent territory in light of historical facts and based on international law.
The landing was totally unacceptable and extremely regrettable, Namazu said.