South Korean authorities are vowing to use all legal measures to stop Japan from carrying out a survey in what they view as South Korean territorial waters. A dispute between the two countries over a handful of tiny islands has gone on for decades, but Seoul says Tokyo is now heightening tensions by unilaterally announcing a research project in the area.

Officials in Seoul said Monday the South Korean coast guard had stepped up vigilance around a chain of disputed islets to block a planned ocean survey by Japanese vessels.

South Korean President Roh Moo-hyun held a cabinet meeting Monday to discuss what authorities here are describing as provocation by Japan.

Tokyo recently notified the International Hydrographic Organization in Monaco it is planning the survey of the sea between Japan and South Korea to update its maps. The project is to start before the end of June and will include the waters surrounding the disputed islands, which South Korea controls, but Japan also claims.

South Korean authorities say Japan should have sought Seoul's permission for the survey. South Korean Foreign Minister Ban Ki-moon warns his country will not tolerate a violation of its sovereignty.

Ban says if Japan intrudes into South Korean waters despite Seoul's objection, South Korea will prevent it by international and domestic law.

Seo Young-gyo, deputy spokesman for President Roh's Uri party, used heated language to respond to the Japanese announcement.

Seo insists Japan must stop what he calls an "invasion plan," and says the Uri party will mobilize every means to deal with the situation.

South Korea maintains a small police presence on the islands, which Seoul calls the Dokdo and Tokyo calls the Takeshima. The dispute is extremely sensitive in South Korea. For many people here, it calls to mind painful memories of Japan's harsh 35-year colonial rule over the Korean peninsula in the early 20th century.

South Korean authorities say Japan has not distanced itself sufficiently from its imperial past.

The dispute has gone on since the end of World War II.

A U.S. Embassy spokesman in Seoul says Washington accepts the existing situation and has not taken a position on the future status of the islands.

The United States says South Korea and Japan should handle their dispute peacefully one-on-one, rather than seeking arbitration in an international court.