WASHINGTON/BEIJING - Brief smiles and handshakes by U.S. and Chinese military leaders at a luxury hotel in Singapore on Friday belie a deep freeze in communications between the two armed forces that is becoming a growing worry at the Pentagon.

U.S. Defense Secretary Lloyd Austin had sought a proper meeting with his Chinese counterpart at the annual Shangri-la Dialogue but Beijing refused. Instead, the retired U.S. Army general had to settle for a quick exchange at a dinner ahead of a weekend full of meetings among Asian military leaders.

The awkward encounter is just the latest example of what U.S. officials and analysts say is a troubling disparity between how the two countries view military risks, with the United States pushing for more and deeper military communications and China reluctant to engage.

Relations between the superpowers are increasingly acrimonious, with friction over issues from Taiwan and China's military activity in the South China Sea to U.S. efforts to hold back China's semiconductor industry.

The U.S. military has responded by pushing for open lines of communication with their Chinese counterparts - both at senior and working levels - to mitigate the risk of potential flare-ups, something it has long advocated.

China's leaders, by contrast, have been slow to establish military contacts and quick to shut them down during periods of diplomatic tension. After the U.S. downed an alleged Chinese spy balloon earlier this year the phone lines went silent and have stayed that way, say U.S. officials.

This has frustrated the United States.

"We have had a lot of difficulty in terms of when we have proposed phone calls, proposed meetings and dialogues," said Ely Ratner, U.S. assistant secretary of defense for the Indo-Pacific, speaking at event last week.

"We ... have had an outstretched hand on this question of military-to-military engagement and we have yet to have a consistently willing partner."

Liu Pengyu, spokesperson at the Chinese embassy in Washington, said on Friday in an emailed statement that communication between China and the United States was conducive to a greater mutual understanding.

"However, now the U.S. says it wants to speak to the Chinese side while seeking to suppress China through all possible means and continue imposing sanctions on Chinese officials, institutions and companies," the statement said. "Is there any sincerity in and significance of any communication like this?"

RISKS AND BENEFITS

China had an obvious reason to push back on a meeting between Austin and China's Minister of National Defense Li Shangfu: Li has been under U.S. sanctions since 2018 over the purchase of combat aircraft and equipment from Russia's main arms exporter.

Zhu Feng, dean of the School of International Studies at Nanjing University, said Beijing believed the sanctions on Li showed that the United States was not sincere in efforts to talk with China.

"The main reason why China is reluctant to have its defense minister meet with the U.S. is because we think dialogue must be on equal terms," Zhu said.

But other factors lie behind this, say analysts, including a different assessment of the risks and benefits and divergent approaches to negotiation.

While neither country wants an accidental military clash, China believes the U.S. military is operating in its sphere of influence, including in the South China Sea and around Taiwan.

As a result, China's leaders don't believe it's in their interest to use military talks to lower U.S. anxieties, said Jacob Stokes, a senior fellow at the Center for a New American Security.

"China wants the United States and its partners to feel worried about rising military and security risks in East Asia and then for Washington change its operational behavior to something that Beijing views as less threatening," he said.

Yun Sun, director of the China program at the Stimson Center, adds that China also sees the risks as lower than the U.S. does.

"Especially given the ongoing Ukraine war, the Chinese don’t quite see the danger of getting into a military conflict with U.S. as significant. Had they believed the threat is higher, they would adopt a different attitude toward the mil-to-mil dialogue,” said Sun.

Then there is China's view of how military talks fit into the broader U.S.-China relationship. The United States may want to keep security-related discussions on a separate track, but Chinese leaders would rather keep the focus on trade and economic issues. From that perspective, military talks are something to bargain with.

"Beijing is clearly favoring the economic relationship with American business and government over the more contentious political and defense channels," said Daniel Russel, the top diplomat for East Asia under Obama, now with Asia Society Policy Institute.

CIA director William Burns visited China last month and held talks with Chinese counterparts to emphasize "the importance of maintaining open lines of communication in intelligence channels," a U.S. official said on Friday.

COLLISIONS AND EMERGENCY LANDINGS

An accidental military clash with China is not a theoretical danger.

In 2001 a U.S. spy plane made an emergency landing on Hainan island after a collision with a Chinese fighter jet.

One Chinese pilot died and Beijing detained the 24-member U.S. crew for 11 days, releasing them only after Washington sent a letter saying it was "very sorry."

A senior U.S. defense official, speaking on the condition of anonymity, said that since 2021 China had declined or not responded to over a dozen requests to talk with the Pentagon and nearly ten working-level engagement requests.

The responses vary but, as with the latest snub, the answer from Beijing is no, one official said, without offering details.

"Frankly, it’s just the latest in a litany of excuses," the senior U.S. official said.

(Reporting by Idrees Ali, Phil Stewart, David Brunnstrom, Michael Martina, Yew Lun Tian, Martina Pollard and Laurie Chen. Editing by Don Durfee, Alistair Bell and Gerry Doyle)