A Chinese spokesman issued a strongly worded demand on Sunday for Japan to "treat calmly" Chinese citizens who have begun a voyage to declare Chinese sovereignty over the Diaoyu Islands in the East China Sea.

Spokesman Liu Jianchao told Japan not to take any action that would jeopardize the Chinese citizens' safety.

He said that the Diaoyu Islands have always been part of Chinese territory and China has indisputable sovereignty over them. He stressed that the Chinese government is unswerving in its will and determination to safeguard the sovereignty over the Diaoyu Islands and the attached islets.

"China has always proposed to resolve the dispute through negotiations," Liu noted.