President Joe Biden has assured his Ukrainian counterpart, Volodymyr Zelensky, that the United States would respond “swiftly and decisively” to a Russian invasion of the former Soviet state.
Biden spoke to Zelensky on the phone on Sunday a day after his hour-long call with Russian President Vladimir Putin failed to produce a breakthrough in what US officials say is a rapidly deteriorating crisis.
"President Biden made clear that the United States would respond swiftly and decisively, together with its allies and partners, to any further Russian aggression against Ukraine,” according to the White House readout.
“The two leaders agreed on the importance of continuing to pursue diplomacy and deterrence in response to Russia's military build-up on Ukraine's borders," it said.
A senior Ukrainian official with knowledge of the conversation told CNN that Zelensky renewed his calls for Washington to provide greater military and financial support to Ukraine and invited Biden to visit Kiev as soon as possible.
“I’m convinced that your arrival in Kiev in the coming days, which are crucial for stabilizing the situation, will be a powerful signal and contribute to de-escalation,” the presidential office quoted Zelenskyy as saying in a statement.
Zelensky also emphasized to Biden the need for a significant financial package for Ukraine, said the official.
The phone call came amid US warnings that a Russian invasion of Ukraine could be imminent. The Ukrainian president, however, has played down fears of an imminent attack and expressed frustration with increasingly dire assessments from the US and NATO.
Earlier, National Security Advisor Jake Sullivan told CBS News that there has been a “dramatic acceleration” in the buildup of Russian forces along the border with Ukraine and that they “could launch a military action, essentially at any time.”
“We also are watching very carefully for the possibility that there is a pretext or a false flag operation to kick off the Russian action in which Russian intelligence services conduct some kind of attack on Russian proxy forces in eastern Ukraine or on Russian citizens, and then blame it on the Ukrainians,” Sullivan said.
US officials estimate that Russia has amassed around 100,000 on the Ukrainian border, with thousands added this week, in preparation for an invasion.
Russia says it is not planning a military attack, and that the buildup is in response to NATO expansion in Eastern Europe, which it sees as a threat to its security.
The United States has rejected a series of security proposals that Russia has put forth in an attempt to resolve the conflict, including a demand that Ukraine not be allowed to join NATO.
Ukrainian Defense Minister Oleksii Reznikov said on Twitter that Kiev had so far received almost 1,500 tonnes of ammunition from allies delivered on 17 flights, including about 180 tonnes from the United States.