(Bloomberg) -- The US ambassador to China called on the Foreign Ministry in Beijing to stop spreading Russia’s “lies,” in an unusually direct and public rebuke by the top American diplomat in the country. 

Ambassador Nicholas Burns made the “request” in response to a question at a government-backed forum Monday about what China could do to resolve the crisis over Russia’s invasion of Ukraine. Burns reiterated President Joe Biden’s call for Beijing to avoid helping Moscow carry out the war, before pivoting to a simmering point of contention between the world’s two largest economies. 

“I would hope that Chinese foreign ministry spokespersons would stop accusing NATO of starting this war. That’s Russian propaganda,” Burns told the World Peace Forum organized by Tsinghua University. “I hope Foreign Ministry spokespersons would also stop telling lies about American bioweapons labs, which do not exist in Ukraine.

“These all came from Russia. Unfortunately, this has been picked up by the Chinese,” Burns added. 

While China has said it doesn’t support the war and urged talks to end the fighting, top officials and state media have repeatedly blamed the US for provoking Russia by allowing the North Atlantic Treaty Organization’s expansion. Diplomats including Foreign Ministry spokespeople Hua Chunying and Zhao Lijian have also used official platforms to amplify Russian-backed conspiracy theories that the US was producing biological weapons in Ukraine.

The US denies the claims and has previously accused China of spreading disinformation, and Burns’s call came at a gathering likely to get the Foreign Ministry’s attention. Tsinghua organizes the forum with approval from the State Council and assistance from Chinese People’s Institute of Foreign Affairs, a think tank. 

The Chinese Foreign Ministry didn’t immediate response to a request for comment on Burns’s remarks Monday. 

Moments before Burns spoke, Andrey Denisov, Russia’s ambassador to China, praised Beijing for its “reasonable and balanced” approach and noted its continued relationship with Kyiv. “That’s why I hope China can signal to our Ukraine neighbors to be more realistic in their approach of the assessment of the situation,” Denisov said. 

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