The United States and Russia exchanged warnings over Ukraine on Thursday, but remained optimistic that talks in the new year could ease spiraling tensions.
In a nearly one hour call, U.S. President Joe Biden told his Russian counterpart Vladimir Putin that he needed to see Russia de-escalate its recent military build-up near Ukraine and threatened unprecedented sanctions if Russia chose to invade its neighbor.
Putin said sanctions from Washington and its allies could rupture diplomatic ties.
After the call, White House press secretary Jen Psaki said in a statement, "President Biden reiterated that substantive progress in these dialogues can occur only in an environment of de-escalation rather than escalation.”
Thursday’s call was the second this month between the two leaders and was requested by Putin.
An aid to the Kremlin said Putin was optimistic the meeting created a "good backdrop" for future talks.
Officials on both sides described the tone of the call as serious without any significant progress towards a resolution.
The exchange sets the stage for lower-level engagement between the countries in January, including a U.S.-Russia security meeting, a Russia-NATO session and a broader global conference.