A Shimane Prefecture firm whose president is the mayor of Okinoshima, the municipality Japan argues has jurisdiction over the South Korea-controlled Takeshima Islands, in 2007 sold a high-speed ship to a South Korean company operating passenger services to the disputed islets.

"There were no other buyers," Okinoshima Mayor Kazuhisa Matsuda said Saturday. "At the time, we didn't know whether the South Korean company was operating a ship that goes to the Takeshima (isles)."

The islets lie roughly halfway between the two countries in the Sea of Japan. They have been administered since the 1950s by South Korea, which calls them Dokdo, but are also claimed by Japan as an inherent part of Shimane.

The South Korean firm, Daea Express Shipping, said the vessel in question has never been used ferry passengers to the Takeshima Islands, adding it has been plying the Busan to Fukuoka route. The company has been running passenger ship services connecting South Korea's Ulleungdo Island and the disputed islets since around 2005.

The Shimane firm, Oki Shinko, said it has asked Daea Express not to use the ship for services to the Takeshima islets.

After business began to slump amid declining passenger traffic, Oki Shinko signed a contract with Daea Express in February 2007 to sell it a high-speed ship for around ¥200 million. The purchase was completed two months later, the sources said.

Oki Shinko is currently in talks with Daea Express over selling it another high-speed vessel for use after the first ship it taken out of service, a move scheduled by the end of November, according to the sources. Daea Express said it has not yet decided how to use the second ship.

Oki Shinko's vessels provide services between the Oki Islands off Shimane, its prefectural capital of Matsue and Sakaiminato in Tottori Prefecture.