Negotiations on a free-trade agreement between Japan and South Korea, already behind schedule, have been further stalled by the territorial dispute over a set of islets in the Sea of Japan, Foreign Minister Nobutaka Machimura said Tuesday.

South Korea was outraged when the Shimane Prefectural Assembly passed an ordinance last week to designate Feb. 22 as "Takeshima Day" in an effort to underscore Japan's sovereignty over the South Korea-controlled islets, called Tok-do in that country.

"The political environment makes it unlikely to allow bilateral (FTA) talks to proceed at this moment," Machimura told his regular news conference. "We agreed to resume talks after the political atmosphere regains calmness."

The two sides initially planned to submit formal trade liberalization proposals in January. But South Korea refused to do so, claiming that Japan's proposal, which it was shown unofficially, was insufficient to start talks, Machimura said.

During informal talks, Seoul offered to remove tariffs on 90 percent of its industrial mining products, according to a Foreign Ministry official. But in return, it urged Japan to do likewise for 90 percent of its agricultural and marine products, which is a politically sensitive matter, the official said.

The Takeshima ordinance was passed at a time when the two sides have been unable to resume FTA talks, Machimura said, adding that a planned visit by farm minister Yoshinobu Shimamura to Seoul in April is likely to be canceled due to the territorial dispute.