TOKYO — Japan plans to explore natural gas fields in a disputed area of the East China Sea that rival China has also been surveying, Japanese media said Tuesday, amid growing tensions between the two countries.

Tokyo has earmarked about 23 billion yen (US $219 million; euro165.06 million) in its budget for the fiscal year starting April 1 for research, test drilling and construction of a ship to survey the sea bed, the mass-circulation Yomiuri newspaper said on its Web site.

The Cabinet is expected to approve the fiscal 2005 budget on Dec. 24 before sending it to Parliament for deliberation, the newspaper said. The Mainichi, another national daily, carried a similar report.

Officials at the Agency of Natural Resources and Energy could not be reached for comment Tuesday.

China's exploration of the disputed area for natural resources has stoked tensions between Asia's two biggest economic powers. Tokyo has also complained about marine surveys it says China has been conducting in Japan's exclusive economic zone in the Pacific Ocean.

Tokyo has demanded that China share information from its explorations in the disputed part of the East China Sea, but Beijing has refused, insisting that its surveys have taken place in Chinese territorial waters.

The U.N. Convention on the Law of the Sea, which both countries have signed, allows coastal countries an economic zone extending 200 nautical miles (230 miles, 370 kilometers) from their shores.

But Beijing and Tokyo, both signatories to the convention, have not agreed where their sea border lies. The United Nations says it will decide on global offshore territorial claims by May 2009.

Japan also alleges that China may be exploring undersea deposits straddling the two countries' respective territories.

Tensions flared last month when Japan detected a Chinese submarine in its waters between the southern island of Okinawa and Taiwan. The Japanese navy went on alert, and followed the vessel out of Japanese waters.

Japan says China later apologized for the incident.

Source: Associated Press