Japan lodged a protest on Friday after South Korea's military and coast guard conducted an "unacceptable" defense drill on disputed islands, the latest flare-up in tension between the two Asian neighbors.

Japan's relations with South Korea have been badly frayed since August 2012 when then-South Korean president Lee Myung-bak visited the islands, known as Takeshima in Japan and Dokdo in Korea. Koreans also harbor bitter resentment of Japanese colonial rule from 1910 to 1945.

Japan summoned a senior envoy at the South Korean embassy in Tokyo, and the Japanese embassy in Seoul also made a protest against the South Korean government, Japanese Chief Cabinet Secretary Yoshihide Suga said.

"In light of our country's stance on the sovereignty of the islands, the drill is unacceptable and highly regrettable," Suga told a news conference.

In the exercise on Friday, the military and the coast guard conducted a joint defense drill with a destroyer and "various vessels" plus air power and navy SEAL agents landing on the islands, half way between the two countries, the South Korean Defense Ministry said.

"Dokdo is historically and substantively our territory and the public nature of the drill is to showcase the military's determination to safeguard it under any circumstances," the ministry said.

Reuters