President Biden holds virtual talks on Dec. 7 with Russian President Vladimir Putin amid Western fears that Moscow plans to attack Ukraine. (Reuters)

President Biden plans to speak with Russian President Vladimir Putin on Thursday afternoon amid tensions surrounding Russia’s military buildup on the border with Ukraine.

During a conversation requested by the Russian government, Biden plans to tell Putin that while the United States is prepared to proceed diplomatically, it also stands ready to respond to further incursions with economic sanctions, NATO reinforcement and assistance to Ukrainian efforts to defend itself, all according to a senior administration official.

The conversation will mark the second Biden-Putin call in a month. In a Dec. 7 videoconference, Biden warned Putin not to mount a new invasion and laid out the economic and security costs that Russia would face if the Kremlin went down that path.

“The Biden Administration continues to engage in extensive diplomacy with our European Allies and partners, consulting and coordinating on a common approach in response to Russia’s military build-up on the border with Ukraine,” said National Security Council spokeswoman Emily Horne in a statement. She said the call would cover “a range of topics, including upcoming diplomatic engagements with Russia.”

The planned call comes during a week when Biden has been away from Washington, splitting his time between Rehoboth Beach and Wilmington, Del., and staying largely out of public view.

Russia is looking to extract security concessions from the United States and its European partners, while simultaneously threatening a new invasion of Ukraine, a U.S. partner nation that is not a member of NATO. Moscow has made several demands, saying Washington needs to provide written guarantees that NATO will no longer expand eastward, a point the White House has dismissed as a nonstarter.

The Biden administration has stressed that Russia will need to begin showing signs of de-escalation before any sort of “diplomatic end game” is possible, a point repeated by the senior administration official previewing the call to reporters on the condition of anonymity under ground rules set by the White House. The official noted that the United States has continued to observe a “significant Russian troop presence” near the Ukrainian border that is not static and continues “to be gravely concerned” about what moves the Russians have been making near the Ukrainian border.

The official said that it was not clear why Putin had requested the call but that “it will take a high level of engagement to address this and to try to find a path of de-escalation.”

“I think both leaders believe that there is genuine value in direct leader-to-leader engagement, that we are in a moment of crisis and have been for some weeks now given the Russian buildup,” the official said.

Biden threatens Putin with economic sanctions if he further invades Ukraine

The administration has previously warned of a variety of responses, which the official reiterated Wednesday. Those include sanctions exceeding those that were imposed in 2014, after Russia annexed the Crimean Peninsula from Ukraine; increasing the U.S. force posture in Europe; and providing Ukraine with additional material assistance to help it defend itself against a potential invasion.

“We are united with our allies in our willingness to engage in principled diplomacy with Russia,” the senior official briefing reporters on Wednesday said, adding that the United States is in close contact with allies and “will proceed on the principle of nothing about them without them.”

Those contacts included a Wednesday conversation between Secretary of State Antony Blinken and Ukrainian President Volodymyr Zelensky.

In a statement, State Department spokesman Ned Price said the call focused on “Russia’s military buildup on Ukraine’s borders, efforts to peacefully resolve the conflict in eastern Ukraine, and upcoming diplomatic engagements with Russia.”

The advertised contacts also include planned meetings of the NATO-Russia Council, as well as the Organization for Security and Cooperation in Europe, and talks between Russia and the United States in Geneva as part of the Strategic Security Dialogue, all expected to take place in the second week of January.

United States and Russian delegations are planning to sit down for security talks on Jan. 10. But the senior administration official previewing the call said, “It is not our expectation that President Biden and President Putin will participate in the session.”

The Biden administration has said that talks must proceed on the basis of reciprocity and that the president plans to bring up concerns that Washington has about Russia’s activities in Ukraine and elsewhere in Europe.

Since October, Putin has massed tens of thousands of Russian troops, as well as materiel, near the border with Ukraine, and the Biden administration has said the Russian military is making plans for a new invasion.

An unclassified U.S. intelligence analysis revealed by The Washington Post earlier this year found that Russia was preparing to move as many as 175,000 forces in preparation for an invasion, though the White House has said Putin hasn’t made a decision yet about whether to launch an offensive. U.S. officials and military analysts have predicted that if Putin decides to proceed, the offensive could take place in late January or February.

The Kremlin has denied any such offensive is in the offing but has taken advantage of the situation to force long-sought, wide-ranging talks with Washington on European security issues.

The White House has said the talks will take place in a variety of formats, not only bilaterally between Washington and Moscow, but also through the NATO-Russia Council and the OSCE. Biden administration officials have emphasized that the United States is not planning to make any deals about security in Europe without the involvement of its European allies.

Paul Sonne contributed to this report.