Defence Secretary Ben Wallace has cut short a family holiday amid fears over the "worsening" crisis in Ukraine.
The UK believes an invasion of the Eastern European country by Vladimir Putin's Russia is "highly likely" and could come any day.
The Cabinet minister revealed on Twitter on Sunday afternoon that he would end a planned half-term break with his wife and three children.
He said: "Having returned from Moscow early on Saturday morning and because we are concerned about the worsening situation in Ukraine I have cancelled a planned long weekend abroad with my family and will be returning."
Mr Wallace only arrived in the undisclosed country on Saturday, having travelled there following diplomatic talks in Moscow.
It is understood Mr Wallace had accepted he would be leaving the trip early before heading there, rather than the decision coming in light of new information.
A senior defence source said: “As events worsen, the Secretary of State has cut short a planned long weekend with his children for half-term.”
It comes after the Defence Secretary sparked a diplomatic row over an interview he gave the Sunday Times in which he said there was a “whiff of Munich in the air” - referencing the agreement that allowed German annexation of the Sudetenland but failed to prevent the Second World War.
Mr Wallace said Moscow could “launch an offensive at any time”, with an estimated 130,000 Russian troops and heavy firepower amassed along Ukraine’s border.
“It may be that he (Putin) just switches off his tanks and we all go home but there is a whiff of Munich in the air from some in the West,” he added.
The comments were not welcomed by Ukraine, however.
Ambassador to the UK Vadym Prystaiko warned that the panic being caused by the West sounding the alarm could be playing into Russian President Vladimir Putin’s hands.
“It’s not the best time for us to offend our partners in the world, reminding them of this act which actually not bought peace but the opposite, it bought war,” the diplomat told BBC Radio 4’s Broadcasting House programme.
“There’s panic everywhere not just in people’s minds but in financial markets as well,” he added, warning it is “hurting the Ukrainian economy on sort of the same level as people leaving the embassy”.
Northern Ireland Secretary Brandon Lewis said an imminent attack is “entirely possible” but insisted Mr Wallace was not criticising European allies with his Munich remark.
Mr Lewis discussed the optimism of 1938 that diplomacy could prevent European conflict, adding: “It turned out that wasn’t the intent or aim of Adolf Hitler at the time.”
The Northern Ireland Secretary told the BBC’s Sunday Morning programme: “What he’s (Mr Wallace) drawing comparison with is we hope that the conversation that he’s had, that the Foreign Secretary and others… has a positive outcome and Russia does work through and find a diplomatic peaceful way out of this.
“But he’s expressing that concern that we’ve got to also understand the reality that while they’re having these diplomatic conversations Russia has continued to move troops, we’ve got about 130,000 troops on the borders, and therefore we’ve got to be cognisant of the reality that they could move very quick.”
US President Joe Biden warned his Russian counterpart an attack would cause “widespread human suffering” during an hour-long phone call on Saturday.
Mr Biden told Mr Putin an attack would “diminish Russia’s standing” as heightened fears of an attack caused Britain and other allies to urge citizens to flee Ukraine.
US officials have discussed receiving intelligence that Russia is considering Wednesday as a target date to strike, but it was unclear how definitive the intelligence was.
Ukrainian President Volodymyr Zelensky sought to play down the threat, saying: “The best friend of our enemies is panic in our country. And all this information is just provoking panic and can’t help us.”
Russian Foreign Ministry spokeswoman Maria Zakharova accused the White House of stoking “hysteria”.
Diplomatic efforts on Saturday also included French President Emmanuel Macron sharing a call with Mr Putin, but it was understood that Boris Johnson, who spoke to the Russian president earlier this month, did not have any calls with Moscow scheduled.
UK nationals in Ukraine are being urged by the Foreign Office to “leave now while commercial means are still available”.
Western leaders have threatened Moscow with a damaging package of sanctions in the event of a further incursion into Ukrainian soil.
Ukraine is not a Nato member and allies in the defence alliance have said they would not join fighting in Ukraine, but have bolstered forces in neighbouring nations and are threatening widespread sanctions.
Though the Kremlin insists it is not planning an invasion, US intelligence suggests Russia could fabricate a “false flag” pretext to attack.
