U.S. President Joe Biden will speak by phone Thursday with his Russian counterpart, a senior administration official said Wednesday, adding the American leader will seek a diplomatic solution to escalating tension along Russia's border with Ukraine.

“We are prepared for diplomacy and for a diplomatic path forward,” the official told reporters Wednesday. “But we are also prepared to respond if Russia advances with a further invasion of Ukraine.”

The call, requested by Russian President Vladimir Putin, comes ahead of highly anticipated high-level talks in Geneva on January 10. Neither president is expected to participate in those talks, the official said.

This marks the second call this month between the two men, who also spoke in early December over what were then some 70,000 troops gathered on the Russian side of the border, according to intelligence estimates from satellite images. But U.S. intelligence analysts predict that Putin plans to mass as many as 175,000 troops.

The U.S. repeatedly has assured Ukraine of its support, and provided tens of millions of dollars in security assistance. On Wednesday, Secretary of State Antony Blinken spoke to Ukrainian President Volodymyr Zelenskiy. In a statement, Blinken said he “reiterated the United States’ unwavering support for Ukraine’s independence, sovereignty, and territorial integrity in the face of Russia’s military buildup on Ukraine's borders.”

The White House has said, repeatedly, that there will be “significant consequences” if Russia invades. Those include harsh economic sanctions and increased security support for Ukraine.

On Wednesday, Zelenskiy tweeted: “I was assured of full [U.S.] support for [Ukraine] in countering Russian aggression.” He used flag emojis to indicate the countries.

Blinken also spoke with the foreign ministers of Britain, France and Germany on “coordination to deter any further Russian aggression against Ukraine,” State Department spokesman Ned Price said.

The Western foreign ministers “affirmed the consensus among allies and partners to impose massive consequences and severe costs on Russia for such actions,” Price said in a statement.

Kremlin spokesman Dmitry Peskov confirmed the call set for Thursday, adding it would take place in the evening Russian time. On Wednesday Russian Prime Minister Mikhail Mishustin called the heads of state in key neighbors Armenia, Azerbaijan and Belarus.

A spokesperson from the National Security Council told VOA the U.S. is relying on its alliances in the region to reach a diplomatic solution.

“We are unified as an alliance on the consequences Russia would face if it moves on Ukraine,” said the spokesperson, who asked to speak on background when discussing current U.S. policy. “But we are also unified in our willingness to engage in principled diplomacy with Russia. … We will adhere to the principle of 'nothing about our Allies and partners without our Allies and partners, including Ukraine.”

Administration officials have declined to respond publicly to Moscow’s demands, which include that NATO deny membership to Ukraine and that the security alliance reduces its deployments in Central and Eastern Europe.

On Wednesday, the senior administration official said: “Our view is that we can make most progress, actually at the negotiating table sitting across from one another behind closed doors and in close consultation with our allies and partners. So we don’t have any current plans to go publish a document or a draft agreement the way that the Russian side has done.”

Meanwhile, some analysts say they doubt Putin's moves will actually culminate in an invasion. National University of Kyiv Professor Taras Kuzio is one of several analysts who believes that an actual invasion would be costly, lengthy and bloody – and therefore, unlikely.

“If Putin attempts to crush Ukraine with overwhelming military force, he could end up losing the country forever, while also sparking anti-government unrest inside Russia with the potential to threaten the survival of his entire regime,” he wrote. “For a man who has already lived through the collapse of one empire, this might be a risk he is not prepared to take.” (VOA)

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