South Korea "strongly condemns" Japan's approval of high school textbooks renewing territorial claims to the country's easternmost islets of Dokdo, the foreign ministry said Tuesday.

A textbook screening committee under Japan's education ministry approved 296 textbooks for first-year high school students, including 30 kinds for social studies subjects, such as history and geography. The books will be used from next year.

All of the 30 textbooks contain details about the rocky outcroppings, a contrast to the previous state review five years ago when some of the approved social studies texts did not carry the claims.

"We strongly protest that the Japanese government passed the screening of textbooks that have not stated the facts as they are in accordance with its own historical perspective, and we urge that a correction be made immediately," ministry spokesperson Choi Young-sam said in a commentary.  

"In particular, we cannot help but deplore and strongly condemn the approval of the textbooks carrying ungrounded claims to Dokdo, which is clearly our indigenous territory historically, geographically and by international law," Choi said.

The foreign ministry called in a Japanese official in Seoul to lodge a protest. The South Korean government also urged Japan to engage in history education based on the "spirit of responsibility, apology and self-reflection as expressed by itself." 

The revised texts are considered to have reinforced Japan's claims to Dokdo that the islets are its indigenous territory and illegally occupied by South Korea.

In March 2018, the Japanese government revised teaching guidelines to instruct high schools to educate students about its claims to Dokdo in social studies classes.

Textbook publishers are required to reflect the government's teaching guidelines in the content to get state approval for publication.

Japan's renewed claims to the rocky outcroppings came as bilateral relations remain badly frayed over the protracted row stemming from colonial-era history issues of forced labor and sexual slavery, and Tokyo's export curbs on Seoul.

Dokdo has long been a recurring source of tensions between the two neighbors, as Tokyo continues to lay claim to the islets in its policy papers, public statements and school textbooks.

South Korea has been in effective control of Dokdo, with a small police detachment, since its liberation from Japan's 1910-45 colonial rule. (Yonhap)