Updated December 30, 2021 at 7:50 PM ET
President Biden on Thursday afternoon again warned Russian President Vladimir Putin of painful economic consequences should Russian forces invade Ukraine.
But Biden also made clear that the United States sees a diplomatic path forward to address some of Russia's concerns about the expansion of the Western-backed NATO in the region.
The details of Thursday's call were relayed by a senior Biden administration official, speaking on the condition of anonymity.
It was the second time the two leaders spoke this month, as Russia has assembled as many as 100,000 troops along the Ukrainian border, prompting fears of an invasion.
Another administration official has described the situation as a "moment of crisis." U.S. officials say they have not seen any significant signs of de-escalation.
"President Biden urged Russia to de-escalate tensions with Ukraine," White House press secretary Jen Psaki said in a statement after the call. "He made clear that the United States and its allies and partners will respond decisively if Russia further invades Ukraine."
The 50-minute call was "serious and substantive," according to the administration official who briefed reporters Thursday.
The official said the purpose of the call, which Putin requested, was primarily to set the "tone and tenor" for planned security talks between U.S. and Russian officials on Jan. 10 in Geneva.
Biden laid out two paths forward, the official said: "One is a path of diplomacy, leading toward a de-escalation of the situation. The other path is more focused on deterrence, including serious costs and consequences should Russia choose to proceed with a further invasion of Ukraine."
But both leaders acknowledged areas where "meaningful progress" could be made, as well as some areas "where agreements may be impossible," the official said.
Putin aide Yuri Ushakov described the talks as good and frank, but said that Putin warned Biden that his promise of punishing sanctions could lead to a complete breakdown in U.S.-Russian relations that would in the future be seen as a big mistake.
What Putin wants
Putin has made his concerns clear.
He wants written assurances that Ukraine will not be admitted into NATO. He also wants Western troops and arms out of other former Soviet states in Eastern Europe.
The U.S. and its allies have refused any such guarantees, but White House officials said they were open to hearing Russia's concerns about NATO.
In addition to economic sanctions, Biden told Putin in their last call, on Dec. 7, that if Russia were to invade Ukraine, the U.S. would provide additional defensive equipment and supplies to the Ukraine — and potentially deploy U.S troops to other nearby Eastern European countries.
U.S. and Russian leaders will lay out their concerns during the Jan. 10 talks. Moscow is expected to continue the conversation with NATO officials two days later and then after, on Jan. 13, meet separately with the members of the Organization for Security and Co-Operation in Europe, of which Ukraine is a member.
What's the outlook?
Whether there is a resolution that can satisfy Putin's demands and avoid war is unclear.
Samuel Charap, who was a top Russia adviser in the Obama administration, is not optimistic.
"I don't yet see a pathway out of this where everyone can go home and there's no conflict," said Charap, who is now an analyst at the Rand Corporation. "It seems clear to me that Putin is not willing to take away the threat until he gets something. And if he doesn't get something, I think he seems prepared to act."
That Putin called for Thursday's call led some to believe that he may be seeking a way out of the stand-off.
Matthew Rojansky, the director of the Kennan Institute and who is close to the Biden administration, says actions speak louder than words. But he says that Putin must also take into consideration the domestic risks of sending tens of thousands of Russian men and women into battle with such a close neighbor.
"As much as he may want to use force to try to change the reality in Ukraine, he has to be aware that the Russian people are not interested in going to war with Ukraine," Rojanksy said.
The Biden official told reporters that Putin did not share if he had made a decision on whether he would invade Ukraine.
"We're not going to draw conclusions and there were certainly no declarations as to intention from this conversation," the official said. "But regardless, our focus is really on action, and on indicators, not on words at this point."
With reporting from NPR's Charles Maynes in Moscow. contributed to this story
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