NUSA DUA, Indonesia (Reuters) – Chinese Premier Li Keqiang stressed the “irresponsibility” of nuclear threats during a summit in Cambodia, suggesting Beijing is uncomfortable with strategic partner Russia’s nuclear rhetoric, a senior U.S. official said. official on Monday. Lee attended the East Asia Summit on Sunday alongside US President Joe Biden. The Chinese premier “spoke quite extensively about China’s policy toward Ukraine,” said a senior U.S. administration official who briefed reporters ahead of a summit between Biden and Chinese President Xi Jinping on Monday. Lee “was clearly emphasizing sovereignty, the irresponsibility of nuclear threats, the need to ensure that nuclear weapons are not used in the way that some have suggested,” the official said, speaking on condition of anonymity. The West has accused Russia of irresponsible statements about the possible use of nuclear weapons after its invasion of Ukraine in February. Moscow in turn accused the West of “provocative” nuclear rhetoric. The US official said there was “definitely some discomfort in Beijing about what we’ve seen in terms of reckless rhetoric and activity on the part of Russia,” despite official cooperation with Moscow. “I think it’s also undeniable that China is probably surprised and even a little embarrassed by the conduct of Russian military operations,” the official said. Biden at Sunday’s summit in Cambodia said the United States would “vigorously compete” with China while keeping lines of communication open to prevent conflict. Biden and Xi will meet in person on Monday for the first time since Biden took office early last year. Premier Li is expected to be replaced next year and the US official said Washington believed Xi would bring “some new faces” to the meeting with Biden on Monday. (Reporting by Simon Lewis; Additional reporting by Nandita Bose and Humeyra Pamuk; Editing by Tom Hogue)