(Bloomberg) -- China declined a US request for the countries’ defense chiefs to meet this week, Beijing’s latest rebuff of the Biden administration’s efforts to restore ties with key officials amid heightened tensions. 

The US had proposed in May that Secretary of Defense Lloyd Austin meet his counterpart Li Shangfu in Singapore during the Shangri-La Dialogue, a marquee Asia-Pacific security gathering. 

Beijing has now formally closed the door on that offer, Pentagon officials said Monday. China previously demanded that the US lift sanctions imposed on its top general in 2018 for overseeing an arms purchase from Russia before such a meeting could take place. 

In a sign of the tense relationship between the top economies and global powers, the US Defense Department called the decision a “concerning unwillingness” to engage in military discussions.

Liu Pengyu, spokesperson at the Chinese Embassy in Washington, in a statement called on the US to create “favorable” conditions for talks, questioning the “sincerity” of seeking meetings while imposing sanctions.

The lack of dialog raises the danger that an accidental collision or confrontation — in the South China Sea, for example — could escalate out of control, sparking a broader conflict that would be catastrophic for the region and global economy.

President Joe Biden now faces an unappetizing choice — keep sanctions on Li and sacrifice military talks with Beijing, or lift them and risk being seen as soft on China heading into election season. 

The Defense Department “believes strongly in the importance of maintaining open lines of military-to-military communication between Washington and Beijing to ensure that competition does not veer into conflict,” Pentagon Press Secretary Brig. Gen. Pat Ryder said in a statement Monday.

Relations have been rocky since the US slapped sweeping export bans on semiconductor technology, a top US politician visited Taiwan angering Beijing, and an alleged Chinese spy balloon crossed US territory, all obscuring any goodwill gained from a meeting late last year between the US leader and President Xi Jinping. 

Biden, however, said at the Group of Seven summit in Japan this month that relations would “thaw very shortly,” suggesting a long-awaited call with Xi could be imminent. Last week, top commerce officials met face-to-face in Washington, following two-days of talks between National Security Adviser Jake Sullivan and China’s top diplomat in May.

Ali Wyne, a senior analyst at the Eurasia Group Ltd, said Beijing was more willing to resume economic discussions than military dialog with Washington due to broader security issues in the relationship. The Biden administration’s support for Taiwan, a self-ruled island Beijing considers its own territory, has been a flashpoint in recent years.

“It’s in the security realm that distrust between the US and China is most pronounced and differences are most irreconcilable,” said Wyne. “The two countries cannot even agree on the virtues of confidence-building measures, which Beijing views as a pretext for Washington to project greater military power into the Indo-Pacific.”

Going into this week’s summit, the Biden administration had seemingly weighed the possibility of lifting the sanctions on Li. During the G-7 summit this month, the US leader said such a move was “under negotiation right now,” something the State Department later denied.

Li plans to attend the Singapore event from May 31 to June 4, the official Xinhua News Agency reported. He will give a speech and meet Singaporean officials, Xinhua said, citing China’s defense ministry.

Last year, Austin met with then-Chinese Defense Minister Wei Fenghe at the security forum, in talks that a Chinese military spokesman described as a start toward resuming a normal dialog. Then-US House Speaker Nancy Pelosi’s visit to Taiwan two months later saw China suspend military dialog with the US.

As that freeze continues, China maintains Li wouldn’t be on an equal footing with Austin if the sanctions stayed in place, Bloomberg News reported earlier. 

Drew Thompson, a senior fellow at the Lee Kuan Yew School of Public Policy in Singapore, said that even without the US-China bilateral dialog in Singapore there would be “tremendous value” in multilateral engagement.

“The real story is the strengthening and increasing relevance of a regional security architecture that’s turning out to be much more important and valuable than whether the US and China will meet,” he added.

--With assistance from Rebecca Choong Wilkins.

(Updates with details throughout.)

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