South Korea has expressed deep regret over the Japanese government's authorization of elementary school textbooks that dilute the forced nature of wartime labor by Koreans and strengthened territorial claims to the Dokdo islets.

In a statement by a foreign ministry spokesperson on Tuesday, Seoul expressed regret over Tokyo's authorization of textbooks repeating misguided claims that have continued for decades.

The government stressed that Dokdo belongs to Korea historically, geographically and under international law and that Japan's claims to the easternmost islets are unacceptable.

It added that a diluted revision of wording related to wartime forced labor in the books is also regrettable and urged Japan to demonstrate through actions its expressed spirit of apology and self-reflection regarding its past.

The government said an accurate view of history by future generations is the foundation of constructive and future-oriented bilateral relations, calling on the Japanese government to squarely face history and be more responsible in educating its youth.