Japan has confirmed that vessels carrying pipes are sailing in the East China Sea toward two gas fields at the center of an energy and border dispute between Japan and China, the trade minister said Friday.

Economy, Trade and Industry Minister Shoichi Nakagawa told a news conference after the day's Cabinet meeting that Tokyo received information Thursday that the ships are heading to the Tianwaitian and Chunxiao fields. He did not refer to the nationality of the vessels.

Japan has made an inquiry to China over the matter, but Beijing has yet to respond. Japan may lodge a formal protest, depending on the response, the minister suggested.

The development follows a bilateral meeting last week in Tokyo that failed to resolve the dispute, which centers on oil and gas exploration rights to the fields. Japan proposed holding another meeting in Beijing on Oct. 19 to break the deadlock.

Nakagawa said China is scheduled to transport oil from the two fields through pipelines to Shanghai, and natural gas from the fields to Ningbo, Zhejian Province.

The two fields -- named by the Japanese government as Kashi (oak) and Shirakaba (white birch), respectively -- are situated a few kilometers away, on the Chinese side, from the median line that Japan claims separates the two countries' exclusive economic zones.

China does not recognize the line and claims its waters stretch to the edge of the continental shelf up close to Okinawa and encompass Taiwan.

Japan says it saw a Chinese consortium extracting either natural gas or oil from the Tianwaitian field in late September. Full-fledged production at the Chunxiao field is also considered imminent, because Tokyo said it has confirmed that pipes have been laid there.

The dispute stems from Japan's concern that China might siphon off resources that could be buried under the seabed on the Japanese side of the median line, since the underground deposits in the Chinese fields have been found either to be connected to or possibly to extend into the Japanese side.

During the last round of talks in Tokyo, Japan repeated its demand that China immediately stop tapping the fields and present concrete data in reference to them.