BEIJING, May 6 (Xinhua) -- China said Wednesday that a U.S. Navy surveillance ship, which conducted activity in China's exclusive economic zone in the Yellow Sea, violated international and Chinese laws.

"The fact is that the USNS Victorious conducted activities in China's exclusive economic zone in the Yellow Sea without China's permission. China has expressed concern over this issue," Foreign Ministry spokesman Ma Zhaoxu said in a statement.

"We demand that the United States take effective measures to prevent similar acts from happening," Ma said.

Ma's comments came in response to a question concerning a Pentagon spokesman's remarks Tuesday that Chinese fishing vessels "harassed" the USNS Victorious in international waters in the Yellow Sea last Friday.

"The Chinese government always handles foreign vessels' activities in China's exclusive economic zones strictly in accordance with the UN Convention on the Law of the Sea, the Law on the Exclusive Economic Zone and the Continental Shelf of the People's Republic of China, and the Regulations of the People's Republic of China on the Management of Foreign-related Marine Scientific Research," said Ma.