A Russian invasion of Ukraine could come at “any time”, possibly within the next two days or before the Winter Olympics finish, a top White House official said on Friday as he urged Americans to leave the country immediately.
The assessment came as the Pentagon announced it was sending an additional 3,000 US troops to Poland, bringing renewed urgency to the Ukraine crisis that has been escalating since November. A growing consensus in US national security circles is that an invasion as imminent, even though Russia denies it will attack.
“We are in the window when an invasion could begin at any time, should [President] Vladimir Putin decide to order it,” National Security Adviser Jake Sullivan told a White House briefing.
“I will not comment on the details of our intelligence information, but I do want to be clear: It could begin during the Olympics, despite a lot of speculation that it will only happen after the Olympics.”
The Beijing Winter Olympics run until February 20.
Mr Putin met with Chinese President Xi Jinping at the opening of the Games, where the Russian leader praised ties with Beijing.
Many observers had thought Mr Putin would not start any military action until after the Olympics.
The US is not certain Mr Putin has ordered an invasion, Mr Sullivan said, and he reiterated that a diplomatic resolution remained a possibility.
But he said a major military operation could start rapidly.
“We can’t pinpoint the day at this point, and we can’t pinpoint the hour, but that is a very, very distinct possibility,” Mr Sullivan said.
“The strong possibility of action, the distinct possibility of action, in a relatively near-term time frame … is backed up by our view of what’s happening on the ground.”
A Russian attack on Ukraine would likely start with an air assault, he said, urging any Americans in Ukraine to leave in the next 24-48 hours.
A senior defence official told Pentagon reporters on Friday that the US is sending another 3,000 combat troops to Poland to join 1,700 who already are assembling there in a demonstration of American commitment to Nato.
The additional soldiers will depart their post at Fort Bragg, North Carolina, over the next couple of days and they should be in Poland by early next week. Their mission will be to train and provide deterrence but not to engage in combat in Ukraine, the official said.
A White House said later that President Joe Biden and Mr Putin would speak on Saturday.
"Russia proposed a call Monday. We counter-proposed Saturday, and they accepted," the official said.
Earlier, as Moscow further stiffened its response to western diplomacy, commercial satellite images from a private US company showed new Russian military deployments at several sites near the border.
Continuing its military build-up near Ukraine, Russia has moved six amphibious assault vessels into the Black Sea, augmenting its capability to land marines on the coast.
Moscow denies it is planning to invade Ukraine.
After telling NBC News that things in Ukraine “could go crazy quickly”, Mr Biden held a phone call on the crisis with the leaders of Britain, Canada, France, Germany, Poland and Romania, as well as the heads of Nato and the EU.
Following that meeting and with alarm spreading, British Prime Minister Boris Johnson joined a handful of other nations in urging UK citizens to leave Ukraine.
Australia and New Zealand on Saturday became the latest countries to ask citizens to leave Ukraine, joining Britain, Japan, Latvia, Norway and the Netherlands. Israel said it was evacuating relatives of embassy staff.
Agencies contributed to this report