A group of Japanese activists are back in their country after abandoning an attempt to land on Dokdo Islets.

Four right-wing Japanese activists arrived at Japan's Oki Islands Wednesday aboard a 6-ton boat enroute to Dokdo to protest South Korea's claim to the rocky volcanic outcroppings.

Their attempt was apparently dissuaded by a Japanese maritime patrol boat which had escorted them to Oki Islands.

In Seoul, Foreign Minister Ban Ki-moon expressed regret over the incident.

The ministry earlier it would sternly deal with any attempt by the Japanese to land on the islets and threatened to seize their boat and arrest them if they violate South Korea's territorial waters.

The islets, known as Takeshima in Japan, have been at the center of a long-running dispute between the two countries. Seoul holds that the islets belong to South Korea, but that Japan began to claim sovereignty over them after it colonized the Korean Peninsula in the early 20th century.