By Charles Scanlon
BBC News, Seoul
South Korea anger has often been directed at Japan in recent years
A row has flared up between South Korea and Japan over Japan's plans to conduct a maritime survey near disputed islands midway between the two countries.
South Korea has sent 20 patrol boats to the area near the islands, known as Dokdo in Korea and Takeshima in Japan.
The Japanese government says it will go ahead with the survey despite warnings.
The dispute over the islands is a recurring flashpoint in relations between South Korea and Japan.
But Tokyo has become increasingly assertive in its claim to sovereignty and that has provoked an angry response from the South Korean government.
Two Japanese coastguard vessels are reported to be on their way to the area around the islands to conduct a maritime survey.
South Korea has responded by sending 20 patrol boats backed by helicopters and reconnaissance planes.
Known as Dokdo (Solitary islands) in Korea, Takeshima (Bamboo islands) in Japan
Also known as Liancourt rocks
Japan's and South Korea's claims go back centuries, but islands occupied by S Korea since 1953
Just 230,000 sq m in size, with no fresh water
But surrounding waters valuable for their fishing
South Korean Foreign Minister Ban Ki-Moon said they were prepared for all eventualities and responsibility for any trouble would lie with Japan.
The isolated rocks have no settled population, but have been occupied for decades by South Korean police.
Mr Ban said Japan's move was not an isolated incident, but an extension of its efforts to distort history.
In recent years, South Korea has condemned visits by the Japanese prime minister to the controversial Yasukuni war shrine.
Japan's chief government spokesman, Shinzo Abe, said the coastguard would continue calmly with its activities in accordance with international law.
He called on both sides to handle the dispute diplomatically.