South Korea has rejected Japan's proposal for foreign ministerial talks on the sidelines of a regional security forum in Singapore next week, a government source said on Thursday.
Seoul turned down the idea after Japan on Monday reaffirmed its claim to South Korean-controlled islands, the source told AFP.
South Korean Foreign Minister Yu Myung-Hwan is, however, set to hold bilateral talks with his counterparts from the United States, Russia and China during the annual ASEAN Regional Forum.
Japan Monday published new educational guidelines calling on students to have a deeper understanding of their country's claim to islands in the Sea of Japan (East Sea), known as Takeshima in Japan and Dokdo in South Korea.
It called for calm over the dispute but the move sparked a furore in Seoul.
About 30 labour activists hurled rotten eggs and tomatoes at the Japanese embassy on Wednesday. President Lee Myung-Bak has ruled out any diplomatic compromise over the issue.
South Korea recalled its ambassador to Japan, Kwon Chul-Hyun, in protest after he had met officials in Tokyo to voice his government's displeasure.
Kwon told the Munhwa Ilbo newspaper on Wednesday that the row could lead to cancellation of a visit by Prime Minister Yasuo Fukuda to Seoul this autumn.
When Lee met Fukuda in Tokyo in April, they agreed to focus on the future of their relationship rather than on Japan's brutal 20th century colonisation of the Korean peninsula.
They also agreed to resume twice-yearly summits suspended in 2005.
South Korea stations a small unit of maritime police on the rugged and treeless islands.
Japan claimed them in 1905 after winning a war with Russia in the region. It went on to annex the entire Korean peninsula from 1910 until its 1945 defeat in World War II.