On Sunday, US President Joe Biden and Ukrainian counterpart Volodymyr Zelensky are due to speak on the phone amid growing fears that a Russian military buildup near the border with its pro-Western neighbor will cause an invasion.
The show of US support for Ukraine came days after Biden warned Russian President Vladimir Putin of the serious consequences if Moscow invades the former Soviet country.
Biden said Friday that he can't invade Ukraine, because he can't negotiate in public, but he made it clear that he can't, using some of his most direct language yet. The US leader said in remarks to reporters during a holiday stay in Delaware that he had made it clear to President Putin that we will have severe sanctions, we will increase our presence in Europe, with NATO allies if Russia invades Ukraine.
In Sunday's call with Zelensky, Biden will reaffirm US support for Ukraine's sovereignty and territorial integrity, review preparations for upcoming diplomatic engagements to help de-escalate the situation in the region, and review preparations for Russia's military build-up on Ukraine's borders. Zelensky tweeted: Look forward to talking to POTUS this Sunday to coordinate our steps for the sake of peace in Ukraine and security in Europe. Washington and its European allies accuse Russia of threatening Ukraine with a new invasion.
About 100,000 Russian troops are massed near the border of the country, where Putin already seized the Crimea region in 2014 and is accused of fomenting a pro-Russian separatist war that erupted in the east in the same year.
Moscow describes the troop presence as a protection against the expansion of NATO, although Ukraine has not been offered membership in the military alliance.
High-ranking US and Russian officials are due to sit down in Geneva on January 9 and 10 to discuss the crisis.
Blinken spoke to NATO chief Jens Stoltenberg on Friday, and Blinken urged Russia to engage meaningfully in the upcoming talks on the tense standoff between Moscow and Kiev.
Stoltenberg said NATO was united and prepared for dialogue. In Thursday's call, Biden warned against invading Ukraine, and the Kremlin leader said anti-Moscow sanctions would be a colossal mistake. Both presidents indicated support for further diplomacy after a 50 minute phone call in just over three weeks.
Foreign policy adviser Yury Ushakov told reporters that Putin was pleased with the talks.
A senior US official, who spoke on condition of anonymity, said the tone was serious and substantive. There was no disguising the depth of disagreement or the dangerously high stakes on the fringes of eastern Europe.