WASHINGTON, March 13 (Reuters) - U.S. National Security Adviser Jake Sullivan, who is due to meet with China's top diplomat Yang Jiechi in Rome on Monday, warned Beijing that it would "absolutely" face consequences if it helped Moscow evade sweeping sanctions over the war in Ukraine.

Sullivan told CNN on Sunday the United States believed China was aware that Russia was planning some action in Ukraine before the invasion took place, although Beijing may not have understood the full extent of what was planned.

Now, he said, Washington was watching closely to see to what extent Beijing provided economic or material support to Russia, and would impose consequences if that occurred.

"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. "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."

A senior Biden administration official said the war in Ukraine and its impact on regional and global security would be a "significant topic" during Sullivan's meeting with Yang, given China's moves to align "itself with Russia to advance their own vision of the world order.

The meeting, which had been in planning for some time, is part of a broader effort by Washington and Beijing to maintain open channels of communication and manage competition between the world's two largest economies, the official said.

No specific outcomes were expected from the meeting, the source added, speaking on condition of anonymity.

Wang Huiyao, head of a Beijing think tank and adviser to the Chinese government, warned of "an escalatory spiral" in a column published in the New York Times on Sunday, and said China was "uniquely positioned to act as a neutral mediator between a Western-supported Ukraine and Russia" to end the war.

"Unpalatable as some in the West may find the idea, it is time to offer the Russian leader an offramp with China’s help," Wang wrote.

The United States on Saturday said it would rush up to $200 million worth of additional weapons to Ukrainian forces as they try to defend against Russian shelling in the largest war in Europe since World War Two. read more

The Russian assault, which Moscow calls a "special military operation," has trapped thousands of civilians in besieged cities and sent 2.5 million Ukrainians fleeing to neighboring countries. read more

READ MORE

• Ukraine says Russia strikes large military base near Polish border killing 35 people
• 'Destroying Russia': Why Putin can't win
• Has Xi Jinping miscalculated in aligning himself with Vladimir Putin?
• China calls Russia its chief 'strategic partner' despite war

The United States and its allies have imposed sweeping, unprecedented sanctions against Russia and banned its energy imports, while providing billions of dollars of military and humanitarian assistance to Ukraine. read more

Individually and together they have appealed to China, Gulf nations and others that have failed to condemn the Russian invasion to join in isolating Russia from the global economy.

Beijing, a key trading partner of Russia, has refused to call Russia's actions an invasion, although Chinese President Xi Jinping last week did call for "maximum restraint" in Ukraine after a virtual meeting with German Chancellor Olaf Scholz and French President Emmanuel Macron. read more

Xi also expressed concern about the impact of sanctions on global finance, energy supplies, transportation and supply chains, amid growing signs that Western sanctions are limiting China's ability to buy Russian oil. read more

Hu Xijin, former editor-in-chief of the state-backed Chinese Global Times newspaper, said on Twitter: "If Sullivan thinks he can persuade China to participate in sanctions against Russia, he will be disappointed."

International Monetary Fund Managing Director Kristalina Georgieva last week said the crisis could also see China miss its 5.5% growth target this year. She said she had spoken with China's top central banker and expected mounting pressure on Russia to end the war.

While in Rome, Sullivan will also meet with Luigi Mattiolo, diplomatic adviser to Italian Prime Minister Mario Draghi to continue coordinating the strong global response to Russian President Vladimir Putin's "war of choice," the source said.

The United States and the Group of Seven advanced economies on Friday ratcheted up pressure on Russia by calling for revoking its "most favored nation" trade status, which would allow them to jack up tariffs on Russian goods.
Trade made up about 46% of Russia's economy in 2020, much of that with China, its biggest export destination.