A group of South Korean lawmakers from the ruling and opposition parties visited their country's easternmost islets of Dokdo on Monday as the nation celebrated the 71st anniversary of Korea's liberation from Japan's 1910-45 colonial rule.

The group of 10 lawmakers, led by Saenuri Party Rep. Na Kyung-won, said the trip was intended to reassert South Korea's sovereignty of the islets and was an "inherent" part of their parliamentary activities.

It is the first such trip by South Korean lawmakers since Aug. 14, 2013, when another group of lawmakers traveled to the islets to counter Japan's territorial claims to Dokdo.

Besides Na, who is a four-term lawmaker and former head of the parliament's Foreign Affairs and Unification Committee, six lawmakers from the ruling party, along with two from the main opposition Minjoo Party of Korea and one from the minor opposition People's Party, visited Dokdo.

On the same day, Han Sang-ki, the administrative chief of Taean County, South Chungcheong Province, also traveled to Dokdo and handed a stone from South Korea's westernmost archipelago in the county to Choi Soo-il, the head of Uleung County, to which Dokdo belongs.

The handover of the stone was a symbolic move to underscore South Korea's territorial right to the islets in the East Sea.

Tokyo's Chief Cabinet Secretary Yoshihide Suga expressed regrets over the lawmakers' visit to Dokdo.

South Korea maintains that Dokdo is its territory "historically, geographically and by international law."

South Korea has been in effective control of the islets since the Korean Peninsula's liberation from Japan in 1945. It has held drills to defend Dokdo twice a year since 1986. (Yonhap)