According to the White House, Biden stated that the United States and its allies would respond decisively and impose swiftly and severe costs to any Kremlin attack on its neighbor.
Biden's national security advisor Jake Sullivan warned that a Russian invasion could occur within days. This warning came just days before the Winter Olympics in Beijing ended on February 20th.
Russia denies that it intends to invade Ukraine, but has gathered well over 100,000 troops close to the Ukrainian border. It has also sent troops to exercises to neighboring Belarus and encircled Ukraine from three sides. Officials from the United States claim that Russia's firepower has reached a point where it can invade Ukraine on short notice.
This conversation occurred at an important moment in what has been the most serious security crisis between Russia's and the West since the Cold War. Officials from the United States believe that they have only days to stop an invasion of Ukraine and massive bloodshed in Ukraine. While the U.S. and NATO allies do not plan to send troops to Ukraine in order to defeat Russia, an invasion of Ukraine and the resulting sanctions could have a devastating impact on energy supplies and the power balance within Europe.
"President Biden made it clear to President Putin that the United States is ready to engage in diplomacy in full coordination and with our Allies, but we are equally prepared for any other scenario," stated the White House.
According to a senior official in the administration who briefed reporters after the call, the call was "professional" and "substantial", but did not produce "no fundamental shift in the dynamic that has been unfolding for many weeks," according the spokesperson.
According to the official, it is not clear if Putin has taken a final decision to continue military action.
Putin's top foreign policy advisor, Yuri Ushakov said that tensions have been increasing for months but "the situation has just been brought to absurdity".
Biden was mentioned by him, but he said that this issue was not the main focus of their lengthy conversation.
Putin spoke to Biden before he called French President Emmanuel Macron by telephone. He met with Putin in Moscow earlier this week to discuss the crisis. According to the Kremlin, little progress was made in cooling the tensions.
Putin complained that NATO and the United States have not responded to Russian demands for Ukraine's exclusion from the military alliance, and that NATO withdraw its forces from Eastern Europe.
The United States has announced plans for the evacuation of most of its staff from its embassy in Kiev, a sign that they are preparing for the worst. Britain joined other European countries in asking its citizens to leave Ukraine.
Canada has closed its Kyiv embassy and moved its diplomat staff to Lviv, in the west part of the country. Foreign Affairs Minister Melanie Joly announced Saturday. Lviv is the home of a Ukrainian military base, which has been the hub for Canada’s 200-soldier soldier training mission in the former Soviet Union.
It remained crucial to determine the timing of any Russian military action.
According to an American official, intelligence indicating that Russia was looking at Wednesday as a target date was seized by the U.S. The unnamed official was not allowed to speak publicly, and spoke only under condition of anonymity.
Antony Blinken, U.S. Secretary-of-State, said that he had told his Russian counterpart on Saturday that any further Russian aggression would be met by a united transatlantic response.
While the Ukrainian President Volodymyr Zelenskyy attempted to project calm, he was watching military exercises Saturday near Crimea. This is the peninsula Russia took from Ukraine in 2014.
He said, "We're not afraid, and we're not panicking, everything is under control."
The joint statement by Oleksiy Reznikov, Defense Minister and Chief Commander of the Ukrainian Armed Forces, was more feisty.
They said, "We are ready for the enemy to face us, not with flowers but with Stingers Javelins, and NLAWs" -- antitank and -aircraft weapon. "Welcome back to hell!"
On Saturday, Lloyd Austin, the U.S. Defense Secretary, and Sergei Shoigu (his Russian counterpart), also had telephone conversations.
The Defense Ministry summoned US Embassy's military attache on Saturday to discuss further tensions between the U.S. and Russia. It was reported that the navy had detected an American sub-marine in Russian waters close to the Kuril Islands in Pacific. The ministry stated that the submarine refused to leave but left after the navy used an unspecified "appropriate method".
To add to the crisis, the Pentagon sent 3,000 additional U.S. soldiers to Poland to assure allies.
The U.S. has urged all Americans living in Ukraine to evacuate immediately. Sullivan stated that those who are still there should not expect the U.S. military rescue in case of an attack by Russia on their air or rail transport.
Although the Biden administration has warned for weeks about Russia's imminent invasion of Ukraine, U.S. officials previously stated that Russia would wait until after the Winter Games to do so in order not to provoke China.
Sullivan said that U.S. intelligence has shown that Russia could invade the Olympics. He suggested that military action could begin with missile and air strikes, then be followed by a ground offensive.
Sullivan stated that Russia has all the necessary forces to carry out a major military operation. He also said that Russia could decide to launch a major military attack against Ukraine in a very short time.
Russia laughed at U.S. claims of urgency.
Maria Zakharova (Russian Foreign Ministry spokesperson) said that "the hysteria surrounding the White House is more revealing than ever." "The Anglo-Saxons require a war. Any cost. They love to use threats, misinformation, and provocations to solve their own problems.
Zakharova stated that her country had "optimized staffing at its embassy in Kyiv" in response to possible military actions by the Ukrainian side.
The Russians also deployed special operations forces, missile, air and naval forces along the Ukraine's southern and eastern borders. Russia has moved six amphibious assault vessels into the Black Sea this week, increasing its ability to land marines along the coast.
As a reassurance to NATO's eastern flank allies, Biden has increased the U.S. military presence. These additional 3,700 soldiers are joining 1,700 already on their way to Poland. The U.S. Army is also moving 1,000 soldiers from Germany into Romania. Romania shares a border to Ukraine, like Poland.
Russia demands that NATO keep ex-Soviet countries out. Russia also demands that NATO refrain from deploying weapons close to its borders and reduce the number of alliance forces from Eastern Europe. These requests are flatly rejected.
Since 2014, Ukraine's Kremlin-friendly leader was forced from power by a popular uprising. Russia and Ukraine are locked in bitter conflict. Moscow responded by annexed the Crimean Peninsula, and then supported a separatist insurgency within eastern Ukraine where over 14,000 people have been killed.
France and Germany brokered a 2015 peace agreement that helped to end large-scale fighting. However, regular skirmishes continue and attempts to reach a political solution have been stalled.
