A group of South Korean lawmakers on Monday visited a pair of islets controlled by South Korea but also claimed by Japan, drawing a formal protest from Tokyo.
The eight-member bipartisan group, led by Na Kyung-won of the main opposition Liberty Korea Party, intends to inspect security facilities on the islets, known as Takeshima in Japan and Dokdo in South Korea, the group said.
Monday's trip to the disputed islets in the Sea of Japan followed a similar visit by another group of South Korean lawmakers on Oct. 22, which was led by the chairman of the National Assembly's Education Committee.
The Japanese government immediately lodged a protest with the South Korean government through diplomatic channels both in Tokyo and Seoul as Japan views Takeshima as an inherent part of its territory, the Japanese Foreign Ministry said.
Kenji Kanasugi, director general of the ministry's Asian and Oceanian Affairs Bureau, conveyed to a senior South Korean Embassy official in Tokyo that the lawmakers' visit is "totally unacceptable" to Japan, according to the ministry.
Na's group, formed to support South Korean security personnel stationed on the islets, had increased the money it was spending on repair and upgrade work at the facilities following its previous visit in August, according to the group.
South Korea has stationed security personnel on the islets since 1954 and constructed lodgings, a monitoring facility, a lighthouse, and port and docking facilities.
The islets are located roughly an equal distance from the Korean Peninsula and Japan's main island Honshu.