President Biden's high-stakes phone call with Russian President Vladimir Putin got underway Saturday as tensions over Ukraine reached a fever pitch, The New York Post reported. 

The conversation, arranged on Friday, came at what Secretary of State Antony Blinken called "a pivotal moment" of diplomacy as Russia continued to mass more than 130,000 troops and heavy military equipment along its border with Ukraine.

Biden was secluded at Camp David, the presidential retreat in the Maryland mountains, for the call, his first direct conversation with Putin since December.

They spoke soon after Putin wrapped up a lengthy conversation with French President Emmanuel Macron in which the two discussed “the conditions for security and stability in Europe,” the Élysée Palace said Saturday.

Earlier Saturday, the US and its Western allies began to evacuate their embassies in Kyiv. A small core of American diplomats would remain in Ukraine, the State Department said — but would relocate to the city of Lviv in western Ukraine, where they could be more easily evacuated if a Russian invasion begins.

About 150 American military trainers, members of the Florida National Guard who have been in Ukraine to help its forces prepare for a potential invasion, are being pulled from the country, the Pentagon announced Saturday.

(With input from agencies)