BEIJING - The United States has been urged not to take sides in the China-Japan territory dispute concerning the Diaoyu Islands, a Chinese Foreign Ministry spokeswoman said on Tuesday.

The remarks of Hua Chunying came in response to a Pentagon report questioning China's straight baseline claims around the Diaoyu Islands in the East China Sea.

The annual Pentagon report, released on Monday, said in September 2012 China began using improperly drawn straight baseline claims around the Diaoyu Islands, adding to its network of maritime claims inconsistent with international law.

Hua reaffirmed that the Diaoyu Islands and their adjacent islets have been the Chinese territory since ancient times, and China owns indisputable sovereignty over the islands.

The Chinese government has drawn the straight baseline of the Diaoyu Islands and their adjacent islets fully in compliance with the United Nations Convention on the Law of the Sea and relevant international practices, Hua told a daily press briefing.

The United States has repeatedly said it does not have a position on the island dispute. "We hope the US will match its words with its actions," the spokeswoman said.

She urged the US side to do more that will help regional peace and stability and not to send wrong signals.