The United States should be just as concerned as other countries about a rise in Japanese nationalism, China's ambassador to Washington said, hinting that the United States should not offer Japan encouragement in its dispute with China over a group of islets.
China and Japan are involved in an increasingly bitter stand-off over the uninhabited islands in the East China Sea, called Senkaku by Japan and Diaoyu by China, which lie atop of possibly large energy reserves.
Beijing last month protested a voyage by 10 boats carrying Japanese activists into waters near the islands.
While tensions flared between Japan and China and South Korea last month after Japanese lawmakers visited a shrine seen by China and Korea as a symbol of Japan's past militarism.
"What kind of message does this send to the international community?" Cui Tiankai, China's ambassador in Washington, was cited as saying in a statement issued by the Foreign Ministry on Wednesday.
"All of these kinds of acts have attracted a lot of attention from international public opinion, and I believe that the U.S. cannot not know about this," Cui said.
"The U.S. side should stay alert against the recent provocative actions taken by Japanese political leaders," the official Xinhua news agency cited Cui as saying, in a separate report.
Japan was "clearly" the one acting provocatively over the islands, not China, he added.
"We hope that other parties do not lift up rocks for the Japanese, and we hope even more that these rocks don't end up falling on their own feet," Cui said, in apparent reference to United States support for Japan over the islands.
Cui also expressed the hope that "Washington will avoid repeating the same mistake by sacrificing its long-term benefits for immediate short-term needs on the issue of the Diaoyu Islands", Xinhua added.
The United States has said that it does not have a position on the island dispute.
However, the U.S.-Japan security treaty commits the United States to intervene in defence of Japan if there is an attack on Japanese-administered territory.