CIA chief William Burns visited China last month, a U.S. official said Friday, as Washington seeks to resume high-level communications with Beijing in spite of heightened tensions between the two countries.

The official, who spoke on condition of anonymity, said that the director of the Central Intelligence Agency traveled to Beijing "where he met with Chinese counterparts and emphasized the importance of maintaining open lines of communication in intelligence channels."

The secret mission by Burns, one of President Joe Biden's closest confidants, marked the highest-level known trip by a U.S. official to China in many months, as bilateral ties further deteriorated earlier this year after the United States shot down what it described as a Chinese spy balloon traveling over its territory.

CIA chief William Burns. (Getty/Kyodo)

The visit, first reported by the Financial Times, became known after Biden dropped a hint during a press conference about two weeks ago in the Japanese city of Hiroshima, saying of the soured U.S.-China relationship, "I think you're going to see that begin to thaw very shortly."

On Friday, Biden's security adviser Jake Sullivan said the United States wants to engage with China and is available for military-to-military dialogue, just after the defense chiefs of the two countries exchanged greetings at a security forum in Singapore.

"We're available for strategic discussions" on topics ranging from outer space and cyberspace to nuclear issues, Sullivan said at a meeting in Washington hosted by the Arms Control Association.

But Sullivan said the United States will not beg China to come to the table. "We just say, 'We're ready to talk when you're ready to talk,'" he said.

He underscored that such dialogue is necessary to manage competition responsibly and minimize the risk of conflict, adding, "Frankly, the rest of the world should look at this question and say, 'What does it mean to be a responsible, significant power in the world?'"

"Doesn't it mean actually being prepared to engage in military-to-military communications, particularly where our militaries are operating in close proximity and where these strategic issues have deep and fundamental stakes for the entire world? I think most countries would answer that, 'Yes,'" he said.

His remarks came after U.S. Defense Secretary Lloyd Austin shook hands with his Chinese counterpart Li Shangfu and spoke briefly with him on Friday during a dinner to open the annual Shangri-La Dialogue.

Austin and Li "did not have a substantive exchange," according to U.S. Defense Department spokesman Pat Ryder.

Amid escalated tensions over Taiwan, Russia's war against Ukraine and many other issues, China had rejected a U.S. request to arrange an official meeting between the defense chiefs on the margins of the three-day security forum.

China severed military-to-military communication channels with the United States after then House of Representatives Speaker Nancy Pelosi visited Taiwan in August, becoming the most senior U.S. official to set foot on the democratic island in a quarter century.

About a week before the G-7 summit was held in the Japanese city in mid-May, Sullivan and China's top diplomat Wang Yi had more than eight hours of what both governments called "candid, substantive and constructive" talks in Vienna in an apparent bid to break the impasse.

Sullivan revealed Friday that he broached issues with Wang such as the importance of restoring lines of communication between senior military officials and engaging with China on nuclear arms control "without preconditions."

"We will continue to indicate our willingness to participate in these discussions on a going-forward basis, and we'll see what (China) chooses to do," he said.

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