China said its relations with Japan were severely hurt on Sunday after Japan decided to prolong the detention of a Chinese trawler captain, warning to take "strong counter measures" if Japan insists its mistakes.

"We demand the Japanese side immediately release the Chinese captain unconditionally," said Foreign Ministry spokesman Ma Zhaoxu.

"China will take strong counter measures if the Japanese side clings obstinately to its own course and double its mistakes, and Japan shall bear all the consequences," Ma said in a press release.

China has already suspended bilateral exchanges at and above the provincial or ministerial levels, Xinhua learnt from the Foreign Ministry.

China has also halted contact with Japan on the issues of increasing civil flights and expanding aviation rights between the two countries.

A bilateral meeting on coal has also been postponed.

In the mean time, the number of Chinese citizens traveling to Japan as tourists has already declined, according to the ministry.