The Chinese Foreign Ministry issued its vehement warning after a Japanese court on September 10 authorized a 10-day extension of the detention of a Chinese captain whose fishing boat collided with two Japanese coast guard ships in disputed seas this week.

The arrest of the captain and continued detention of 14 crew members has created an emotive focus in the long-running territorial quarrels between Beijing and Tokyo over East China Sea islets, called Senkaku in Japan and Diaoyu in China.

Beijing postponed a round of talks with Tokyo intended to settle their dispute over East China Sea gas fields, Chinese Foreign Ministry spokeswoman Jiang Yu said in a statement on the Chinese Foreign Ministry web site (www.mfa.gov.cn) late on September 10.

On September 11, Japan lodged a protest with China after a Chinese State Oceanic Administration ship attempted to stop a Japanese Coast Guard vessel from conducting an oceanic survey 280 km northwest of Japan's southern Okinawa island.

A source in the Japanese prime minister's office said it was "regrettable that the postponement (of the talks) was announced unilaterally," according to Kyodo news agency.

Broader contention over the disputed seas could unsettle ties between Asia's two biggest economies. After big public protests and bitter diplomatic exchanges sparked rows in 2005 and 2006, both sides have sought to improve ties.

Tokyo maintains that China's exploration for natural gas in the East China Sea threatens gas beds extending under what it deems Japan's maritime zone. China denies there is such a problem and disputes Japan's definition of the sea boundary.

In 2008, they agreed in principle to solve the dispute by jointly developing gas fields. Talks began in July on a treaty, but the postponement of the next round of talks will hold back prospects for progress in the dispute.