A satellite image shows a close-up of troops and equipment at Oktyabrskoye air base, Crimea February 10, 2022. 2022 Maxar Technologies/Handout via REUTERS
A satellite image shows a close-up of troops and equipment at Oktyabrskoye air base, Crimea February 10, 2022. 2022 Maxar Technologies/Handout via REUTERS Reuters / MAXAR TECHNOLOGIES

Russia has massed enough troops near Ukraine to launch a major invasion, Washington said on Friday, as it urged all U.S. citizens to leave the country within 48 hours after Moscow further stiffened its response to Western diplomacy.

A Russian attack could begin any day and would likely start with an air assault, White House national security adviser Jake Sullivan said.

He said U.S. intelligence believed a rapid assault on Kyiv was also a possibility, and that Russian President Vladimir Putin could order an invasion before the end of the Winter Games in Beijing on Feb. 20.

It however remained unclear whether Putin had definitively given that order, Sullivan told a media briefing.

Putin and U.S. President Joe Biden will speak by phone on Saturday, according to a White House official and Russia's RIA news agency. Russia's TASS news agency said Putin will speak with French President Emmanuel Macron on the same day.

Four U.S. officials told Reuters on Friday that Washington will send 3,000 extra troops to Poland in coming days to try and help reassure NATO allies. They are in addition to 8,500 already on alert for deployment to Europe if needed.

Earlier, commercial satellite images from a U.S. firm showed new Russian military deployments at several sites near the border.

After telling NBC News that things in Ukraine "could go crazy quickly," Biden held a 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.

The leaders raised concerns about Russia's military buildup, expressed a desire for a diplomatic solution, and agreed to make coordinated efforts to deter Russian aggression, including by being ready to impose "massive consequences and severe economic costs" on Moscow if it chose military escalation, the White House said after the call.

Russia's foreign ministry said Western countries, with help from the media, were spreading false information to try to distract attention from their own aggressive actions.

'DEVASTATING AND DESTRUCTIVE'

Prime Minister Boris Johnson of Britain, which joined a handful of other nations in urging their citizens to leave Ukraine, told the call hosted by Biden that he feared for the security of Europe.

He stressed the need for "a heavy package of economic sanctions ready to go, should Russia make the devastating and destructive decision to invade Ukraine," Johnson's office said.

Japan, Latvia, Norway and the Netherlands also told their citizens to leave Ukraine immediately. Israel said it was evacuating relatives of embassy staff.

Moscow, meanwhile, said answers sent this week by the EU and NATO to its security demands showed "disrespect".

Biden met his national security advisers overnight, a source familiar with the meeting said. U.S. officials believed the crisis could be reaching a critical point, with rhetoric from Moscow hardening, six Russian warships reaching the Black Sea, and more Russian military equipment arriving in Belarus, the source said.

"We're in a window when an invasion could begin at any time, and to be clear, that includes during the Olympics," said Secretary of State Antony Blinken. The Beijing Games end on Feb. 20.

"We continue to see very troubling signs of Russian escalation, including new forces arriving at the Ukrainian border," Blinken said.

Stocks extended declines in the late afternoon, with the S&P 500 index recently down around 1.9%. Gold and oil prices rose.

'IMPOLITENESS AND DISRESPECT'

Russia has already massed more than 100,000 troops near Ukraine, and this week launched joint military exercises in neighbouring Belarus and naval drills in the Black Sea.

Moscow denies planning to invade Ukraine, but says it could take unspecified "military-technical" action unless a series of demands are met, including promises from NATO never to admit Ukraine and to withdraw forces from Eastern Europe.

The West has said those main demands are non-starters. The EU and NATO alliance delivered responses this week on behalf of their member states.

Russia's foreign ministry said it wanted individual answers from each country, and called the collective response "a sign of diplomatic impoliteness and disrespect".

Several Western countries launched diplomatic pushes this week to persuade Russia to back down, but Moscow brushed them off, yielding no concessions to Macron, who visited on Monday, and openly mocking British Foreign Secretary Liz Truss when she came on Thursday.

Four-way talks in Berlin between Russia, Ukraine, Germany and France on Thursday also yielded no progress.