South Korea denounced Japan Friday after Tokyo issued a diplomatic report renewing the country's claims to the South's easternmost islets of Dokdo.

The annual report, Diplomatic Bluebook 2016, was reported to the Cabinet with claims that Dokdo is clearly Japanese territory historically and under international law.

"It is beyond deplorable that the Japanese government repeated its unjustified territorial claims to Dokdo, which is our territory historically, geographically and by international law," Cho June-hyuck, a spokesman of Seoul's Foreign Ministry, said in a statement. "We demand an immediate withdrawal of the (claim)."

Cho urged Japan to stop its "futile claims" and work to open a "new future" for bilateral relations by squarely facing up to history.

Last month, Tokyo also approved a set of updated high school textbooks that repeated Japan's territorial claims to Dokdo. The authorization represented a bolstering of the claims because 27 of the newly approved 35 social studies textbooks -- or nearly 80 percent -- accused South Korea of "illegally occupying" the islets.

South Korea rejects the claims as nonsense because the country regained independence from Japan's 35-year colonial rule in 1945 and reclaimed sovereignty over its territory, including Dokdo and many other islands around the Korean Peninsula.

The ministry is expected to lodge a protest with the Tokyo government by calling in a Japanese Embassy official later in the day.

Dokdo, a pair of outcroppings lying in the East Sea, has long been a thorn in bilateral relations. Seoul effectively controls the islets with a police detachment stationed there since 1954.

The report still referred to South Korea as Japan's "most important neighbor that shares strategic interests," saying Tokyo will improve bilateral relations following last year's agreement to resolve the issue of Japan's wartime sexual enslavement of Korean women.

The accord will be the key to opening a "new era" in the two countries' ties, it added.

Last year's report referred to the South simply as the "most important neighbor," which marked a toning down from the 2014 report that said the two countries share basic values and interests, such as free democracy and basic human rights. (Yonhap)