US President Joe Biden was clear that, if Moscow undertakes a further invasion of Ukraine, the US together with our Allies and partners "will respond decisively and impose swift and severe costs on Russia", the White House announced on Saturday.
Russian President Vladimir Putin and US President Joe Biden held a high-stakes telephone call as tensions over a possibly imminent invasion of Ukraine escalated sharply the day before.
"While the United States remains prepared to engage in diplomacy, in full coordination with our Allies and partners, we are equally prepared for other scenarios," the readout stated.
Before talking to Biden, Putin spoke with French President Emmanuel Macron, who said that the two agree on the need to seek a diplomatic means to end the crisis during their telephone conversation. The two met in Moscow earlier in the week -- a visit that the Elysée Palace said showed progress in attempts to lower the tensions.
Meanwhile, Ukrainian President Volodymyr Zelenskyy slammed the latest US claims that the Kremlin is planning an invasion as soon as early next week, saying that they are "causing panic and not helping".
"We are not afraid, we're without panic, all is under control,” he said as he observed military exercises Saturday near Crimea, the peninsula that Russia seized from Ukraine in 2014.
"Currently, the best friend of our enemies is panic in our country. And all this information only causes panic and does not help us," Zelenskyy said.
Also, the US embassy in Ukraine has officially withdrawn its non-essential staff, while Germany and Lithuania joined a number of countries advising their citizens to leave due to increased threat levels.
Russia has massed troops near the Ukraine border and sent troops to neighbouring Belarus for joint exercises. Still, the Kremlin insistently denies that it intends to launch an offensive against Kyiv.
Adding to the sense of crisis, the Pentagon ordered an additional 3,000 US troops to Poland to reassure allies.
Biden has said the US military would not enter a war in Ukraine, but he has promised severe economic sanctions against Moscow in concert with international allies.
Macron: Putin 'expressed desire' for a diplomatic solution
French President Emmanuel Macron warned his Russian counterpart Vladimir Putin on Saturday that a "sincere dialogue is not compatible with a military escalation" on the Ukrainian border, the Elysée Palace said after an almost two-hour-long telephone conversation between the two heads of state.
During the discussion, Macron and Putin "both expressed a desire to continue the dialogue" on "ways to move forward on the implementation of the Minsk agreements" on Donbas and on "the conditions for security and stability in Europe", the French presidency added.
The French president also "relayed the concerns of his European partners and allies," it said.
The discussion between Macron and Putin follows their five-hour tête-à-tête in the Kremlin on Monday before Macron travelled to Kyiv on Tuesday for talks with Ukrainian Zelenskyy and then to Berlin.
The Elysée Palace said the diplomatic tour had achieved its "objective" by making "progress" in lowering the tensions between Russia and Ukraine.
France has not yet asked its nationals to leave Ukraine, unlike many other Western countries.
Countries urge citizens to leave as tensions increase
The timing of any possible Russian military action remains a crucial question.
According to a US official familiar with the findings, the US acquired intelligence that Russia is looking at Wednesday as a target date.
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 US does not know with certainty whether Putin is committed to invasion.
However, US officials said anew that Russia's buildup of offensive air, land and sea firepower near Ukraine had reached the point where it could invade on short notice.
The US State Department ordered the withdrawal of its non-essential staff "due to continued reports of a Russian military build-up on the border with Ukraine, an indicator of potential significant military action," the embassy in Kyiv posted on Twitter on Saturday.
Earlier, a similar order was issued, asking families of embassy staffers in Kyiv to leave. Non-essential personnel were given the option to remain prior to the latest decision.
The White House also urged all US citizens in Ukraine to leave, emphasizing that they should not expect the US military to rescue them if air and rail transportation were severed after a Russian invasion.
Several countries, including the UK, Germany, Lithuania, Norway, Denmark and Israel, also asked their citizens to leave Ukraine.
The German Foreign Ministry said on Saturday that German citizens who are not there for "essential" reasons should leave Ukraine, where "military conflict cannot be ruled out" in the short term.
"Tensions between Russia and Ukraine have increased in recent days due to the presence and massive movements of Russian military units near the Ukrainian borders," the ministry stated on its website, warning in its "recommendations" to travellers that "a military conflict cannot be ruled out".
"If you are currently in Ukraine, make sure that your presence is essential. If not, leave the country at short notice," the ministry said.
Meanwhile, the Russian embassy in Ukraine has reduced its diplomatic staff out of fear of "provocations by the Kyiv regime or third countries".
Foreign ministry spokeswoman Maria Zakharova said on Saturday morning that the country has “optimised” staffing at its embassy in Kyiv.
“We conclude that our American and British colleagues apparently know about some military actions being prepared in Ukraine that could significantly complicate the situation in the security sphere,” she said in a statement.
Some believe that the move was decided upon to incite further panic among Ukrainians and the country's Western allies.
Russia dismisses US fears of imminent invasion
US top diplomat Antony Blinken said the path for talks remained "open" in order to avoid conflict in Ukraine but that Moscow has to de-escalate in a phone call with his Russian counterpart Sergei Lavrov on Saturday, the State Department said.
The secretary of state "made it clear that a diplomatic path to resolving the crisis remains open, but that it would require de-escalation by Moscow and good-faith discussions," State Department spokesman Ned Price said.
An invasion of Ukraine, which Russia is accused of preparing, "would result in a resolute, massive and united transatlantic response," he added.
For his part, Sergei Lavrov described Washington's accusations as "provocations", according to a Russian foreign ministry statement.
Biden's national security adviser, Jake Sullivan, said on Friday evening that 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.
Russia scoffed at the 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 US 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 20 February.
Sullivan said the combination of a further Russian troop buildup on Ukraine's borders and unspecified intelligence indicators had 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.
More US troops sent to NATO's eastern edge
Biden has said US troops will not enter Ukraine to contest any Russian invasion. Yet, he has bolstered the country'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 US Army is also shifting 1,000 soldiers from Germany to Romania, which like Poland shares a border with Ukraine.
Biden spoke to several European leaders on Friday to underscore the most recent concerns. Sullivan said the Western leaders were completely united and would respond harshly to a Russian invasion with devastating economic and trade sanctions.
Russia demands 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 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 the Maidan uprising.
Moscow responded by annexing Crimea and then backing a separatist insurgency in the region of Donbas 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.