South Korea has condemned Japan for publishing a video in 10 languages challenging its sovereignty over a tiny group of islets at the heart of a territorial dispute, demanding Tokyo remove it.
The film, published on Wednesday by the Japanese foreign ministry on its own website and on YouTube, insists the islets, called Dokdo by Seoul and Takeshima by Tokyo, are its own.
The 90-second clip - subtitled and dubbed in 10 languages including English, Korean, Chinese, French, Spanish and Arabic - described Seoul's de facto control over the islets as "illegal".
"We gravely protest the publication of the video … and strongly demand that Japan remove these videos immediately," Seoul's foreign ministry said in a statement.
"We will never tolerate Japan's attempt to violate our territorial sovereignty and will respond resolutely," it said.
The ministry would publish videos on its own website and YouTube that counter Japan's claims in several languages later this month, its spokesman Cho Tai-young said.
The Japanese foreign ministry website also published a multi-language leaflet to accompany the video, arguing that Japan's connection to the islets stretches back more than 200 years.
Japan and South Korea have bickered for decades over control of the islets. The row escalated last year following a surprise visit by then South Korean president Lee Myung-bak. In October, South Korea carried out a military exercise there.
Relations have also been strained by other issues of contention arising from Japan's 1910 to 1945 colonial rule over the Korean peninsula.
Japan is embroiled in a separate row with China over another set of disputed islands. Japan's foreign ministry also published this week a video reasserting its claim to the islands - called the Senkakus by Tokyo and Diaoyus by Beijing - in 10 languages.