Russia could invade `any day` now: US warns Americans in Ukraine to leave within 48 hours

`We continue to see signs of Russian escalation, including new forces arriving at the Ukrainian border,` White House national security adviser Jake Sullivan said.

New Delhi: The United States on Friday (local time) said that Russia could invade Ukraine 'any day' now and warned its citizens in the country to leave within 48 hours.

"We continue to see signs of Russian escalation, including new forces arriving at the Ukrainian border," White House national security adviser Jake Sullivan told reporters and added that "the risk is now high enough and the threat is now immediate enough".

"If a Russian attack on Ukraine proceeds, it is likely to begin with aerial bombing and missile attacks that could obviously kill civilians without regard to their nationality," he added.

US intelligence believes a rapid assault on Kyiv was also possible and that Russian President Vladimir Putin could order an invasion before the Winter Olympics end on February 20, Sullivan said, adding it remains unclear whether such a command has been given.

"And I want to take a moment to echo what both President Biden and Secretary Blinken have already said: We encourage all American citizens who remain in Ukraine to depart immediately. We want to be crystal-clear on this point: Any American in Ukraine should leave as soon as possible, and in any event, in the next 24 to 48 hours," Sullivan said.

He informed that US President Joe Biden also held a secure video conference on Friday with key allies and partners to coordinate their approach to this crisis. 

"The participants were the UK, France, Germany, Italy, Canada, Poland, Romania, the Secretary-General of NATO, and the presidents of the European Union," Sullivan said.

"Whatever happens next, the West is more united than it’s been in years. NATO has been strengthened.  The Alliance is more cohesive, more purposeful, more dynamic than at in any time in recent memory," he added.

Moscow, however, denies planning to invade Ukraine but says it could take unspecified "military-technical" action if its demands are not met.

Russia, notably, has already massed more than 1,00,000 troops near Ukraine, and this week had launched joint military exercises in neighbouring Belarus and naval drills in the Black Sea.

Meanwhile, Biden and Putin plan to have a phone conversation on Saturday.