Britons are being advised against all travel to Ukraine and those already in the country are being told to leave while they can.
The action came as Boris Johnson told world leaders he “feared for the security of Europe” over the threat of a Russian invasion of Ukraine.
In a virtual meeting on Friday evening, the prime minister spoke with the leaders of the US, Italy, Poland, Romania, France, Germany, the EU, and NATO.
“The prime minister told the group that he feared for the security of Europe in the current circumstances,” a Downing Street spokesperson said.
“He impressed the need for NATO allies to make it absolutely clear that there will be a heavy package of economic sanctions ready to go, should Russia make the devastating and destructive decision to invade Ukraine.
“The prime minister added that President Putin had to understand that there would be severe penalties that would be extremely damaging to Russia’s economy, and that allies needed to continue with efforts to reinforce and support the Eastern frontiers of NATO.
“He urged the leaders to work together to deliver economic and defensive support to Ukraine.
“The leaders agreed that if President Putin deescalated, there was another way forward, and they pledged to redouble diplomatic efforts in the coming days.”
UK copies US in advising against all Ukraine travel
On Thursday, the US government advised Americans against travelling to Ukraine due to “the increased threats of Russian military action”.
The State Department also urged all those US citizens currently in Ukraine to leave the country now.
The Foreign Office has now followed the US action and issued updated travel advice on Friday to advise UK citizens “against all travel to Ukraine”.
“British nationals in Ukraine should leave now while commercial means are still available,” the updated advice added.
“Since January 2022, the build-up of Russian forces on Ukraine’s borders has increased the threat of military action.
“Due to this increased threat, the FCDO has taken the decision to further withdraw embassy staff from Kyiv.
“The embassy remains open but will be unable to provide in-person consular assistance. British nationals should leave while commercial options remain.”
Prior to Friday’s updated advice, the Foreign Office had previously advised of only “essential” travel to Ukraine, with only border regions near Russia designated as complete no-go areas.