A U.S. foreign policy expert said in Washington that he believed the U.S. government's position on the Diaoyu islands is "contradictory."

"Because the only way that the U.S.-Japan defense treaty should apply to those islands is if the United States regards them as Japanese territory," Ted Carpenter, senior fellow for defense and foreign policy studies at the Cato Institute, told Xinhua in a recent interview.

"If in fact Washington is neutral about the substance of the dispute, namely, we won't decide whether the islands belong to China or Japan, then clearly the defense treaty should not cover those islands," he said.

"I don't see how the United States gets out of that contradiction," said Carpenter, who is the former vice president for defense and foreign policy studies of the Washington-based think tank.

The United States has said that it does not take a position on the question of the ultimate sovereignty of the Diaoyu Islands, while it also stated that the islands fall under the scope of the U.S.-Japan defense treaty.

But it remains unclear whether Washington regards the Diaoyu Islands as Chinese territory or Japanese territory.

On Tuesday, U.S. State Department spokeswoman Victoria Nuland shunned a question from a Xinhua reporter regarding the territorial belonging of the Diaoyu Islands. Instead, she only reiterated Washington's usual position.

Carpenter believed that the U.S. position on the Diaoyu Islands has the "potential" to escalate the disputes between China and Japan over the islands.

"I believe that the U.S. position should be one of strict neutrality," he said, warning that Washington is "getting entangled in a potentially very difficult and messy dispute."

Commenting on the ongoing U.S.-Japan joint military exercise which reportedly included scenario of island warfare, Carpenter said: "Clearly that does not help the state of tension in the region."

With respect to Washington's true intention behind the Diaoyu Islands dispute, Carpenter bluntly pointed out: "I think that the United States would like to see Japan's position on those islands prevail."

"In a tactical sense, Japan exercises more control over that area than does China. And the U.S. wants the situation to remain that way," he said.

"On the other hand, Washington does not want a crisis with China over that issue," he noted.

But Carpenter did not believe that the United States is ready for the potential crisis aroused from the dispute over the Diaoyu Islands, which historically belongs to China.

"I don't think the U.S. officials have thought the matter through very carefully on what happens if these tensions escalate," he said.

"Shintaro Ishihara, the governor of Tokyo, is tapping into the nationalistic sentiment in Japan. That could make matters far more tense than they have been at this point," Carpenter said. "I don't think the United States is fully prepared to deal with that possibility."