Chinese President Xi Jinping is said to have personally warned Russian President Vladimir Putin not to use nuclear weapons in Ukraine.
According to a Financial Times report citing statements from western and Chinese officials, the warning was delivered during Xi Jinping's state visit to Moscow last March.
Since then, China has privately benefited from convincing the Russian president to withdraw his nuclear threat against Ukraine.
China's foreign affairs ministry did not immediately respond to a request for comment on the matter.
However, a former government official confirmed that Xi told Putin privately not to do so, suggesting China is using the warning as its weapon of peace in Ukraine.
Russia's aggression in Ukraine is heavily dependent on support from Beijing which has helped Moscow to withstand the impact of economic sanctions from Western countries.
Last year, China's two-way trade with Russia reached a record $190 billion, as Beijing increased its purchases of Russian energy and allowed it to import key technologies including microchips.
China has avoided criticizing Russia for the invasion and accused the West of deliberately fueling the conflict by supplying arms to Ukraine.
