Biden and Putin
Biden and PutinReuters

US President Joe Biden and Russian President Vladimir Putin spoke for 50 minutes on Thursday in the hopes of defusing an unremitting crisis on Russia's border with Ukraine, CNN reported.

A statement from the White House said that Biden “urged Russia to de-escalate tensions with Ukraine. He made clear that the United States and its allies and partners will respond decisively if Russia further invades Ukraine.”

“President Biden also expressed support for diplomacy, starting early next year with the bilateral Strategic Stability Dialogue, at NATO through the NATO-Russia Council, and at the Organization for Security and Cooperation in Europe. President Biden reiterated that substantive progress in these dialogues can occur only in an environment of de-escalation rather than escalation,” added the statement.

CNN reported that Putin requested the telephone call this week for reasons US officials said were not precisely clear. Biden and Putin had last spoke on December 7 in a video conference that ended with a pledge to restart diplomatic discussions, but no indication Russia was preparing to deescalate.

Since then, as many as 100,000 Russian troops have remained amassed at the Ukrainian border, despite warnings from Biden and European leaders of serious consequences should Putin move ahead with an invasion.

Biden hoped Thursday's phone call, which the White House said began at 3:35 p.m. ET and ended 50 minutes later, would yield more progress in easing tensions.

US officials said he would tell Putin a pathway exists to avoid conflict -- and by extension avert the withering economic sanctions the West is poised to levy should Russian troops move over the border.

Biden conducted the call from his home in Wilmington, Delaware.

Thursday’s Biden-Putin talks come roughly two weeks before Americans and Russian diplomats are scheduled meet in Geneva to discuss the ongoing crisis.

Since Biden last spoke to Putin, there have not been indications Russia is easing its posture on the border with Ukraine, though a senior administration official said the situation was fluid.

"It is not entirely static from our perspective," the official said, according to CNN. "It remains a continuing source of grave concern what the Russians have been putting in place in and around that border area."