U.S. National Security Adviser Jake Sullivan has warned Beijing it would "absolutely" face consequences if it helped Moscow evade sanctions over the war in Ukraine.

Reports in the US media, citing unnamed officials, claim that Russia asked China to provide military equipment, including drones.

However, the Chinese embassy in Washington said it was not aware of this request.

The warning comes ahead of a meeting in Rome on Monday between top US and China officials.

In a CNN interview, US National Security Adviser Jake Sullivan said they were "communicating directly, privately to Beijing that there will absolutely be consequences for large-scale sanctions evasion efforts or support to Russia to backfill them.

"We will not allow that to go forward and allow there to be a lifeline to Russia from these economic sanctions from any country, anywhere in the world."

Mr Sullivan is due to meet Yang Jiechi, a member of China's top decision-making body the Politburo and the head of the Central Foreign Affairs Commission, on Monday in Rome.

Reuters news agency quoted a US official as saying that during the meeting Mr Sullivan will spell out the consequences and isolation China would face if it increased support for Russia.

Liu Pengyu, a spokesman for China's embassy in Washington DC, told US media that he had not heard of Russia's request. He added: "The high priority now is to prevent the tense situation from escalating or even getting out of control."

China so far has refrained from condemning Russia for the military operation, and has said Moscow's "legitimate security concerns" should be taken seriously.

Also read:  Russia warns US: Western arms convoys to Ukraine will be treated as military targets