Amid the ongoing Ukraine-Russia conflict, United States president Joe Biden’s National Security Adviser Jake Sullivan warned Chinese officials against supporting Russia’s Ukrainian invasion, despite Russia denying reports that it requested Chinese military equipment. Sullivan and senior Chinese Foreign Policy Adviser Yang Jiechi convened in Rome, due to the Biden administration’s increasing concerned that China is using the Ukraine war to advance Beijing’s long-term interest in its competition with the U.S. The Biden administration is seeking clarity on Beijing’s stance on the issue and warning the Chinese that assistance for Russia, including helping avert sanctions imposed by the U.S. and Western allies, would be costly for them.

“The National Security Adviser and our delegation raised directly and very clearly our concerns about the PRC’s [People’s Republic of China] support to Russia in the wake of the invasion, and the implications that any such support would have for the PRC’s relationship not only with us, but for its relationships around the world,” said State Department spokesman Ned Price. “It was an intense seven-hour session reflecting the gravity of the moment as well as our commitment to maintaining open lines of communication,” a senior administration official said, describing the conversation as “candid” and “direct”. Sullivan told CNN before the meeting that the U.S. was “communicating directly, privately to Beijing that there will absolutely be consequences for large-scale sanctions evasion efforts or support to Russia to backfill them.”

China and Russia have deepened their strategic partnership in recent years and China is Russia’s biggest trade partner. Beijing has sent aid to Ukraine while calling for peace, offering to help mediate, but it has aligned rhetorically with Russia, blaming the West and blasting sanctions as counterproductive and bad for the global economy. The U.S. has also accused Beijing of spreading false Russian claims that Ukraine was running chemical and biological weapons labs with U.S. support.

The entire situation at hand is rather precarious, and there have not been any events that indicates any type of imminent chemical or biological attack right now. The striking U.S. accusations about Russian disinformation and Chinese complicity came after Russian Foreign Ministry spokeswoman Maria Zakharova alleged with no evidence that the U.S. was financing Ukrainian chemical and biological weapons labs. The international community for years has assessed that Russia has used chemical weapons in carrying out assassination attempts against Russian president Vladimir Putin’s critics. Russia also supports the Assad government in Syria, which has used chemical weapons against its people in a decade-long civil war.

The Russians have seen significant losses of tanks, helicopters, and other material since the start of the war more than two weeks ago. Ukraine, while overmatched by Russian forces, is well-equipped with anti-tank and anti-aircraft missiles. Russia’s and China’s weapons systems have limited information sharing capabilities, and it’s not clear what weapons China has that Russia would be in short supply of, and what potential aid or gain this could bring.