Japan to China: don't develop gas field on own: media

TOKYO (Reuters) - Japan's ambassador to China, Uichiro Niwa, has told China not to unilaterally develop a gas field in a disputed area of the East China Sea, Kyodo news agency reported on Thursday, as Asia's two biggest economies bicker over rights to territory and resources.

The two countries have been feuding since Japan detained the captain of a Chinese fishing boat trawler that collided with Japan Coast Guard ships off disputed islands in the East China Sea. Japan released the captain last week and on Thursday, China freed three of four Japanese nationals it had detained on suspicion of violating a law regarding military facilities.

Japan and China also have a long-running feud over China's exploration for natural gas in the disputed waters, although in 2008 they agreed in principle to solve the argument by jointly developing the gas fields.

(Reporting by Linda Sieg; Editing by Chris Gallagher)