Before talking to Biden, Putin is to have a call with French President Emmanuel Macron, who met with him in Moscow earlier in the week to try to resolve the crisis.
Russia has massed troops near the Ukraine border and has sent troops to exercises in neighboring Belarus, but insistently denies that it intends to launch an offensive against Ukraine.
Adding to the sense of crisis, the Pentagon ordered an additional 3,000 U.S. troops to Poland to reassure allies.
Biden has said the U.S. military will not enter a war in Ukraine, but he has promised severe economic sanctions against Moscow, in concert with international allies.
The timing of any possible Russian military action remains a key question.
The U.S. picked up intelligence that Russia is looking at Wednesday as a target date, according to a U.S. official familiar with the findings. The official, who was not authorized to speak publicly and did so only on condition of anonymity, would not say how definitive the intelligence was, and the White House publicly underscored that the U.S. does not know with certainty whether Putin is committed to invasion.
However, U.S. officials said anew that Russia’s buildup of offensive air, land and sea firepower near Ukraine has reached the point where it could invade on short notice.
U.S. officials told The Associated Press that the State Department plans to announce Saturday that virtually all American staff at the Kyiv embassy will be required to leave. The State Department would not comment.
The department had earlier ordered families of U.S. embassy staffers in Kyiv to leave. But it had left it to the discretion of nonessential personnel if they wanted to depart.
Biden’s national security adviser, Jake Sullivan, urged all Americans in Ukraine to leave, emphasizing that they should not expect the U.S. military to rescue them in the event that air and rail transportation is severed after a Russian invasion.
Several NATO allies including Britain, Canada, Norway and Denmark also are asking their citizens to leave Ukraine, as is non-NATO ally New Zealand.
Sullivan said Russian military action could start with missile and air attacks, followed by a ground offensive.
“Yes, it is an urgent message because we are in an urgent situation,” he told reporters at the White House.
“Russia has all the forces it needs to conduct a major military action,” Sullivan said, adding, “Russia could choose, in very short order, to commence a major military action against Ukraine.” He said the scale of such an invasion could range from a limited incursion to a strike on Kyiv, the capital.
Russia scoffed at the U.S. talk of urgency.
“The hysteria of the White House is more indicative than ever,” said Russian Foreign Ministry spokeswoman Maria Zakharova. “The Anglo-Saxons need a war. At any cost. Provocations, misinformation and threats are a favorite method of solving their own problems.”
In addition to the more than 100,000 ground troops that U.S. officials say Russia has assembled along Ukraine’s eastern and southern borders, the Russians have deployed missile, air, naval and special operations forces, as well as supplies to sustain a war. This week Russia moved six amphibious assault ships into the Black Sea, augmenting its capability to land marines on the coast.
Sullivan’s stark warning accelerated the projected timeframe for a potential invasion, which many analysts had believed was unlikely until after the Winter Olympics in China end on Feb. 20. Sullivan said the combination of a further Russian troop buildup on Ukraine’s borders and unspecified intelligence indicators have prompted the administration to warn that war could begin any time.
“We can’t pinpoint the day at this point, and we can’t pinpoint the hour, but that is a very, very distinct possibility,” Sullivan said.
Biden has said U.S. troops will not enter Ukraine to contest any Russian invasion, but he has bolstered the U.S. military presence in Europe as reassurance to allies on NATO’s eastern flank. On Friday the Pentagon said Biden ordered a further 3,000 soldiers to Poland, on top of 1,700 who are on their way there. The U.S. Army also is shifting 1,000 soldiers from Germany to Romania, which like Poland shares a border with Ukraine.
Biden spoke to a number of European leaders on Friday to underscore the concerns raised by U.S. intelligence about the potential imminence of a Russian invasion. Sullivan said the Western leaders were completely united and would respond harshly to a Russian invasion with devastating economic and trade sanctions.
Russia is demanding that the West keep Ukraine and other former Soviet countries out of NATO. It also wants NATO to refrain from deploying weapons near its border and to roll back alliance forces from Eastern Europe — demands flatly rejected by the West.
Russia and Ukraine have been locked in a bitter conflict since 2014, when Ukraine’s Kremlin-friendly leader was driven from office by a popular uprising. Moscow responded by annexing Crimea and then backing a separatist insurgency in eastern Ukraine, where fighting has killed over 14,000 people.
A 2015 peace deal brokered by France and Germany helped halt large-scale battles, but regular skirmishes have continued, and efforts to reach a political settlement have stalled.
Matthew Lee and Aamer Madhani in Washington DC contributed to this story.