Still, even as formal talks on A.I. have stalled, scholars from both countries have held informal discussions, often through academic conferences or think tanks. Participants described these meetings as vibrant, and said they have produced many suggestions for cooperation, such as an emergency hotline in case of an A.I.-related accident, or shared standards for testing whether A.I. has the ability to synthesize biohazards.

But these conversations have not been immune from political pressures.

Jiang Tianjiao, a professor at Fudan University in Shanghai who has participated in many discussions with U.S. scholars, said that many Chinese scholars, especially in the security and defense communities, were skeptical of their U.S. counterparts’ intentions. They pointed to Mr. Trump’s efforts to loosen domestic restrictions on A.I. at home as proof that safety discussions were a trap to slow China’s development.

“These people believe the U.S. is talking about one thing but doing the other,” Professor Jiang said, noting that he personally supported continued engagement. In their minds, he said, “China should never trust the United States on any proposals of bilateral A.I. cooperation for all humankind. That’s just some fantasy.”

On the American side, many scholars and officials believe that China is secretly racing toward artificial super-intelligence, though Beijing has made little public mention of it, and Chinese scholars insist that it is not a focus. Beijing has, instead, publicly emphasized practical, real-world applications of A.I.

Then, there are more basic disagreements. For long-running discussions hosted by the Brookings Institution, a Washington-based research institute, and Tsinghua University in Beijing, the participants created a glossary of terms. There was no consensus on the meaning of fundamental terms such as “loss of control” of A.I. systems, said Kyle Chan, a fellow at Brookings.