U.S. official says that Russia asked China for military equipment and support for its war in Ukraine following Vladimir Putin’s full-scale invasion two-and-a-half weeks ago.

“We will not allow that to go forward,” White House national security adviser Jake Sullivan warned the Chinese government ahead of Monday morning talks in Rome between top aides for the U.S. and China.

Sullivan will meet with Yang Jiechi, a member of the Chinese Communist Party’s Politburo and director of the party’s Central Foreign Affairs Commission.