Japanese Foreign Minister Toshimitsu Motegi claimed that Takeshima, referring to the Korean Dokdo islets, belongs to Japan both in the view of historical facts and under international law.

Speaking at the Japanese Diet's regular session which opened on Monday, the minister made the territorial claim and said his country will respond in a stern and cool-headed manner.

Japan laying claim to Dokdo is nothing new, having been included in its diplomatic bluebook published every April.

However the latest claim comes at a more delicate time as Seoul and Tokyo are seeking to resolve the wartime forced labor issue through dialogue.

Meanwhile the Japanese government is opening a new exhibition center on territorial issues in Tokyo on Tuesday, which may further raise tensions with neighboring countries.