By Kanishka Singh
(Reuters) -U.S. national security adviser Jake Sullivan spoke on Wednesday with Nikolay Patrushev, the secretary of Russia's Security Council, in the first high-level contact publicly disclosed between the two countries since the invasion of Ukraine, and warned Patrushev about the consequences "of any possible Russian decision to use chemical or biological weapons in Ukraine."
The White House statement after the call between the two officials did not specify what those consequences would be.
Washington and its allies have accused Russia of spreading an unproven claim that Ukraine had a biological weapons program as a possible prelude to potentially launching its own biological or chemical attacks.
Sullivan told Patrushev that if Russia was serious about diplomacy, then it should stop attacking Ukrainian cities and towns, the White House said in a statement.
Sullivan reiterated the United States' opposition to Russia's invasion of Ukraine and told Patrushev that the U.S. would impose costs on Russia for it, the White House said.
Western countries have been swiftly moving to isolate Russia from world trade and the global financial system after its invasion of Ukraine that began in late February. It is Europe's biggest invasion since World War Two and has destroyed some Ukrainian cities and sent more than 3 million refugees fleeing abroad. Moscow has characterized its actions as a "special military operation."
The U.S. national security adviser, who was among American officials put on a "stop list" on Tuesday that bars them from entering Russia, also mentioned the United States' commitment to reinforce NATO's eastern flank, the White House added.
Earlier in the day, Ukrainian President Volodymyr Zelenskiy urged American lawmakers to do more to protect his country from Russia's invasion in an address before the U.S. Congress.
(Reporting by Kanishka Singh in Bengaluru, Editing by Chris Gallagher)
