China has stepped up its maritime dispute with Japan by halting high-level exchanges over the extended detention of a Chinese fishing boat captain.

State broadcaster CCTV said Beijing had suspended ministerial and provincial-level contacts, including talks on increasing flights, and postponed a meeting on coal.

The row began more than a week ago, when a trawler collided with two Japanese coastguard ships near uninhabited islands in the East China Sea that are claimed by both countries. The two countries have a long history of tensions over territory, resources and other issues.

But after several years of improving relations and increasing trade, they have more to lose if ties are damaged, meaning they will be wary of letting the spat get out of hand.

A foreign ministry statement read out on television said Japan's refusal to release the captain had "already caused serious damage to Sino-Japanese bilateral contacts". Earlier, in a statement on the Chinese foreign ministry website, spokesman Ma Zhaoxu warned: "If Japan insists on making one mistake after another, the Chinese side will take strong countermeasures, and all the consequences should be borne by the Japanese side."

Xinhua news agency added that Chinese vice foreign minister Wang Guangya had expressed "strong indignation" and made "solemn representations" to the Japanese ambassador, Uichiro Niwa, who has been summoned repeatedly since the row began.

"Regarding individual issues, what is needed is to respond calmly without becoming emotional," Noriyuki Shikata, a spokesman for the Japanese prime minister's office, told Reuters.

Takeshi Matsunaga, assistant press secretary for Japan's foreign ministry, said the unilateral steps China had taken were "regrettable".

The court in Okinawa, Japan, said Zhan Qixiong could be held for another 10 days for further questioning. Authorities have released the other 14 crew members. He was arrested on 8 September and under Japanese law prosecutors can hold him for up to 20 days while deciding whether to charge him.

Japan has accused the captain of deliberately striking a patrol ship as it tried to intercept his vessel, and obstructing officers. But China has said the detention is illegal and has repeatedly demanded the authorities free him.

[Source: The Guardian]