Putin and Biden last spoke on the phone late last year. Prior to that, on December 7, they had negotiations via video-conference. The first face-to-face meeting between Putin and Biden as heads of state took place in Geneva in June 2021.

The Russian President has also engaged a series of Western leaders in talks that have so far appeared fruitless in defusing the situation.

Putin’s weekend phone calls follow several warnings on Friday by American and European officials, who expressed concern for the security of Europe and the safety of their citizens in Ukraine.

Biden, who is spending the weekend at Camp David, took part in a virtual meeting from the White House on Friday with leaders from Canada, the United Kingdom, France, Germany, Italy, Poland, Romania, NATO, the European Commission and the European Council to discuss escalating tensions.

Following the call, Biden’s national security adviser, Jake Sullivan, appeared before the press saying that though Putin hasn’t decided whether to act, there is a “very distinct possibility” Russia could swiftly engage in a major military action.

“We obviously cannot predict the future, we don’t know exactly what is going to happen. But the risk is now high enough and the threat is now immediate enough that this is what prudence demands,” he said.

A travel advisory issued by the State Department on Saturday said it had “ordered the departure of most US direct hire employees from Embassy Kyiv due to the continued threat of Russian military action.” Along with the US, several other countries are calling for their citizens to leave Ukraine immediately as well.

It also stated that consular services would be suspended but stressed a small diplomatic presence would be maintained in the city of Lviv in the west of the country, about 50 miles from the Polish border, to handle emergencies.

The Biden administration is discussing the possibility of pulling other US government employees out of Ukraine. On Friday, a British diplomat told CNN that the British Embassy in Kyiv is “temporarily removing all nonessential staff and dependents” and “a core team will remain to continue with essential duties.”

A senior defense official told CNN that Defense Secretary Lloyd Austin had ordered 3,000 more soldiers from the 82nd Airborne Division to deploy to Poland, joining the 1,700 already there. The soldiers are there to help Americans who may try to leave Ukraine.

In Ukraine’s capital, Kyiv, Mayor Vitali Klitschko outlined preparations the city is taking to safeguard “critical and social infrastructure facilities” in “the event of a possible emergency.”

In the statement issued on Telegram ahead of the weekend, Klitschko said, “Our efforts are aimed at preventing or overcoming both possible provocations and withstanding a military attack.”

Klitschko said efforts included generating additional electricity production and creating fuel reserves, as well as organizing the forces for the territorial brigade to defend the city. He also outlined the current state of shelter structures in the city and said evacuation commissions are also being set up.

“Electric generators have been installed for uninterrupted operation in the emergency situation of the city management systems and thermal power plants of the capital for a period of up to 10 days. Businesses have a guaranteed uninterrupted connection in the absence of mobile communications and the Internet,” the statement said.