China released a unilaterally rewritten Chinese-language version of a joint document issued with Japan on the occasion of a recent ministerial economic dialogue in Beijing after both nations agreed on its content and Tokyo wants the version corrected, Foreign Minister Masahiko Komura and a diplomatic source of the two countries said Sunday.

The deleted portions from the joint document released by the Chinese after the first Japan-China High-Level Economic Dialogue in Beijing on Dec. 1 included a phrase in which Japan expressed hope for China's efforts to revalue the yuan.

"I think there were some slip-ups as to why (some portions) were dropped so we are confirming (with China that the document) is supposed to have been agreed in this way," Komura told reporters, referring to the initially agreed text that cited the yuan.

It is extremely unusual for one side to unilaterally rewrite the contents of a joint document that has already been agreed upon and could affect the two nations' efforts to build mutually beneficial strategic relations.

The Beijing meeting took place under a new dialogue framework set up to enhance mutually beneficial economic ties. Six Cabinet members from Tokyo participated and China was represented by Vice Premier Zeng Peiyan and other ministers.

Tokyo released the full text of the document in Japanese to reporters in Beijing on Dec. 1, while China released its version on Dec. 3 and it was posted on the website of China's Commerce Ministry.

The Japanese Embassy in Beijing, however, found out later that the Chinese-language text was different from the initially agreed upon one and that sections referring to Japanese hopes for the yuan's appreciation and the importance of China's participation in the Energy Charter Treaty had been deleted.

A senior Japanese Foreign Ministry official said, "The yuan issue has been getting on China's nerves so it might have resisted putting that issue in writing," but added that the ministry has not yet confirmed if the deletion by China was intentional.

The United States and European nations have repeatedly urged China to adopt a more flexible currency regime, arguing that the yuan is being held artificially low, giving Chinese exports an unfair advantage in world markets.

China remains an observer nation of the Energy Charter Treaty, which stipulates international rules on matters such as energy trade liberalization.