WASHINGTON — Russia asked China to give it military equipment and support for the war in Ukraine after Russian President Vladimir Putin began a full-scale invasion last month, according to U.S. officials.

Russia has also asked China for additional economic assistance, to help counteract the battering its economy has taken from broad sanctions imposed by the United States and European and Asian nations, according to an official.

U.S. officials, determined to keep secret their means of collecting the intelligence on Russia’s requests, declined to describe further the kind of military weapons or aid that Moscow is seeking. The officials also declined to discuss any reaction by China to the requests.

Chinese President Xi Jinping has strengthened a partnership with Putin and has stood by him as Russia has stepped up its military campaign, destroying cities in Ukraine and killing hundreds or thousands of civilians. U.S. officials are watching China closely to see whether it will act on any requests of aid from Russia. Jake Sullivan, White House national security adviser, is scheduled to meet Monday in Rome with Yang Jiechi, a member of the Chinese Communist Party’s elite Politburo and director of the party’s Central Foreign Affairs Commission.

Sullivan intends to warn Yang about any future Chinese efforts to bolster Russia in its war or undercut Ukraine, the United States and their partners.

“We are communicating directly, privately to Beijing, that there will absolutely be consequences for large-scale sanctions evasion efforts or support to Russia to backfill them,” Sullivan said on CNN Sunday.

Sullivan did not make any explicit mention of potential military support from China, but other U.S. officials spoke about the request from Russia on the condition of anonymity because of the sensitivity of diplomatic and intelligence matters.

Liu Pengyu, a spokesperson for the Chinese Embassy in Washington, said he had never heard of the request from Russia. “The current situation in Ukraine is indeed disconcerting,” he said, adding that Beijing wants to see a peaceful settlement. “The high priority now is to prevent the tense situation from escalating or even getting out of control.”

The Biden administration is seeking to lay out for China the consequences of its alignment with Russia and penalties it will incur if it continues or increases its support. Some U.S. officials argue it might be possible to dissuade Beijing from ramping up its assistance to Moscow.

This article originally appeared in The New York Times.