President Lee Myung-bak has warned that the safety of four Japanese lawmakers could be at risk if they press ahead with a trip here seen as aimed at bolstering Tokyo's claims to the South's easternmost island of Dokdo, an official said Wednesday.

Four lawmakers of Japan's opposition Liberal Democratic Party said last week they will visit Ulleung Island near Dokdo in early August in an apparent attempt to renew its territorial claims over the islets in the East Sea between the two countries.

Japan's attempt to lay claims to Dokdo has long been a thorn in relations between the two countries. South Koreans see those claims as a sign that Japan has not fully repented for its 1910-45 colonial rule of the Korean Peninsula.

The planned trip by Japanese lawmakers has sparked outrage in South Korea, with the ruling party chief and other lawmakers calling for the government to ban their entry to the country. By law, Seoul can prohibit people from entering the nation if they are feared to undermine "the interests of the nation or the safety of the public."

The issue was raised Tuesday during the prime minister's weekly report to President Lee.

"If the Japanese lawmakers enter the country for the purpose of visiting Ulleung Island, their safety cannot be guaranteed," Lee was quoted as saying during the meeting, according to presidential spokesman Park Jeong-ha. "How about notifying Japan that it would be better for them not to come to South Korea?"

Lee was voicing concern that the Japanese lawmakers could be a target of angry civic groups.

South Korea's foreign ministry has repeatedly urged the Japanese lawmakers to call off their travel plans. Foreign Minister Kim Sung-hwan conveyed that stance to his Japanese counterpart, Takeaki Matsumoto, during their talks on the sidelines of an Asian security meeting last week, officials said.

South Korea has rejected Japan's claims over Dokdo as nonsense because the country regained independence from colonial rule and reclaimed sovereignty over its territory, including Dokdo and many other islands around the Korean Peninsula. (Yonhap News)