(JI CHUNPENG)

A detained Chinese fishing trawler is tied to a Japanese Coast Guard vessel at a port in Japan's Okinawa Prefecture in this September 9 picture.

The Chinese Foreign Ministry said on September 19 China will take "strong countermeasures if Japan insists on its mistakes," after Japan

decided to prolong the detention of the trawler's captain Zhan Qixiong by 10 days to September 29 despite China's opposition.

Zhan's trawler collided with two Japanese Coast Guard patrol vessels off the Diaoyu Islands in the East China Sea on September 7. He was later held by Japanese authorities for allegedly "obstructing public duties." The 14 fishermen aboard and the trawler were returned by Japan on September 13.

China suspended ministerial and higher level exchanges with Japan as well as bilateral negotiations on increasing air routes between the two countries. Chinese surveillance ships have been dispatched to safeguard China's rights and interests in Chinese waters.

Hundreds protested outside Japanese diplomatic residences across China on September 18.