Western leaders have discussed the security crisis in eastern Europe and the top US general has spoken to his counterparts in Russia and Belarus, amid fresh warnings from Washington that Moscow could launch a new attack on Ukraine at any moment.
The White House said on Friday that a Russian invasion of Ukraine could come within the week, possibly within the next two days. National security adviser Jake Sullivan said the US still did not know if Russian president Vladimir Putin had made a decision to invade, but that all the elements are now in place for a rapid incursion.
US president Joe Biden held a phone conference on Friday with leaders of at least seven other Nato states, including Germany, France and Britain, and top EU officials to discuss "shared concerns about Russia's continued build-up of military forces around Ukraine, and continued co-ordination on both diplomacy and deterrence," the White House said.
Earlier, Mr Biden reiterated a call for American citizens to leave Ukraine as Russia masses some 100,000 troops and heavy weaponry close its borders and threatens to take “military-technical” steps unless the West meets the Kremlin’s security demands – which the US and its allies have repeatedly rejected.
“American citizens should leave, should leave now,” Mr Biden told US television. “We’re dealing with one of the largest armies in the world. This is a very different situation and things could go crazy quickly.”
The UK foreign office on Friday issued new guidance advising British citizens not to travel to Ukraine and for those there to leave now while commercial means are still available.
The Department of Foreign Affairs said there were “no plans to withdraw or evacuate staff from the Irish Embassy in Kyiv at this time”. It was undertaking security and consular planning for “for possible developments in Ukraine, in cooperation with other EU Member States,” a spokeswoman said.
Satellite imagery shows significant Russian forces to the north, east and south of Ukraine, including in Belarus and the Black Sea, along with tanks, missile launchers, fighter jets and electronic warfare systems; experts say Russia also appears to be adding elements – such as medical facilities and fuel supply capacity – that would facilitate a major invasion.
"We're in a window when an invasion could begin at any time," said US secretary of state Antony Blinken, as Mark Milley, chairman of the US joint chiefs of staff, spoke to his counterparts from Russia, Belarus and Britain.
Ukraine and most European states have given lower threat assessments, but the head of military intelligence in Norway, which borders Russia, said on Friday that Moscow could launch a range of operations after massing "more than 150,000 combat troops" near Ukraine.
Vice Admiral Nils Andreas Stensones said the Russians "have all they need to carry everything out, from a minor invasion in the east to minor attacks here and there in Ukraine, or a complete invasion, with, possibly, an occupation of all or parts of Ukraine."
“Now, it is up to President [Vladimir] Putin to choose if he wants to proceed or not,” he added.
British defence secretary Ben Wallace met Russian counterpart Sergei Shoigu for what he called "constructive and frank" talks in Moscow, during which he "heard clearly from the Russian government that they had no intention of invading Ukraine and I also heard some of their concerns".
“When they say to me they are not going to invade Ukraine we will take that seriously but as I also said we will look at the actions that accompany it,” he added.
“The disposition of the Russian forces that we see, over 100,000 ... obviously gives that size of force the ability to do a whole range of actions including an invasion of a neighbouring country at any time.”
Mr Shoigu urged the US, Britain and other allies of Ukraine to stop “stuffing” it with weapons: “It is coming from all sides, it is being done publicly. It is being done in a demonstrative way. It is not entirely clear why,” he said.
A day after frosty talks between the top diplomats of Russia and Britain, Mr Shoigu said that “unfortunately, the level of our co-operation is close to zero and about to cross the zero line and go into negative, which is undesirable.”
Russia has sent several warships into the Black Sea in recent days and announced military drills in the region for next week, but Ukraine said on Friday that Moscow had lifted some associated restrictions that would have severely hampered shipping in the area.
Britain's foreign secretary Liz Truss warned against offering any concessions to Russia which could be perceived as a reward for its threatening behaviour towards Ukraine. Speaking in London a day after she met Russian foreign minister Sergei Lavrov in Moscow, Ms Truss said Nato could not offer a guarantee that Ukraine would not join the alliance.
“I think it’s very important that Russia cannot be rewarded for aggression. So whilst Nato put on the table proposals which are about improving transparency and improving confidence, the demands from Russia to see changes in the ability of sovereign nations to join Nato simply aren’t acceptable.
“And I was in Moscow making that point, which is there cannot be rewards for aggression. Because that would not only send a message to the regime in Moscow, it also sends messages to aggressors around the world. And this is why Nato has to stand strong and firm in response to that,” she told The Irish Times.
Britain has taken a more hawkish stance towards Russia than most other European countries, putting in place new legislation this week to enable a toughening and expansion of sanctions and sending more troops to Estonia. Ms Truss said that if Russia did not intend to invade Ukraine it could de-escalate the crisis by moving its troops away from the border.
"Their threatening behaviour has had the effect of strengthening Nato's resolve, increasing support for Nato, including moving more troops into enhanced forward presence. The United Kingdom is doubling our strength in Estonia, for example, as well as supplying support over the Black Sea.
“It’s also turning people in Ukraine away from Russia. So if you look at Ukrainian support for joining Nato, it was approximately 30 per cent in 2014. Now up to two thirds of Ukrainians support that. So their threatening of Ukraine has had a direct effect on the Ukrainian people,” she said.