The Chinese missile destroyer Jinan prepares to rescue a small naval vessel as part of the first joint military drill to be staged between China and the US in the Atlantic Ocean. The six-hour exercise took place on Saturday and each country sent three warships. ZENG TAO / XINHUA

The United States has undergone several changes of mood in its attitude toward China over the past 10 years, moving from "concern" to "worry" and then to "anxiety", according to a Chinese researcher.

Fan Jishe, a US studies researcher at the Chinese Academy of Social Sciences, was reacting to comments by US Defense Secretary Ash Carter, who expressed concern over China's expanding influence.

Fan is author of the book US Military Strategy in the Post-Cold War Era — Adjustment and Adapting.

Carter said, "In the face of Russia's provocations and China's rise, we must embrace innovative approaches to protect the United States and strengthen that international order."

He made the remarks on Saturday at a forum at the Ronald Reagan Presidential Library and Center for Public Affairs in California.

On the same day, China and the US staged their first joint military drill in history in the Atlantic Ocean, which lasted for six hours. Each side sent three warships.

Referring to the US sending a guided-missile destroyer to sail in waters near Zhubi Reef off China's Nansha Islands in the South China Sea on Oct 27, Carter said, "We've done them (patrols) before, all over the world, and we will do them again."

Carter visited the USS Theodore Roosevelt, an aircraft carrier transiting the South China Sea, on Thursday.

Fan said, "Carter's remarks and the US military's recent moves in the South China Sea demonstrate their anxiety in terms of dealing with China.

"They don't really know what to do. So they just simply chose to take the defensive position. They act tough and want to make the first move in areas that make them feel anxious, like the South China Sea, to show their strength."

Fan said the US has shown "selectivity" over what it tends to believe is China's stance over the South China Sea.

Carter said he has accepted an invitation from Beijing to visit China next year, according to the US Ministry of Defense.