Boris Johnson will tell world leaders during a visit to Germany that there is “still a chance to avoid unnecessary bloodshed” as tension continues to mount between Russia and Ukraine.
The Prime Minister will head to the Munich security conference on Saturday to discuss the crisis with his counterparts following his address to the annual summit.
The trip comes as the US warned an invasion of Ukraine could come within “several days”.
Johnson has previously called the situation in eastern Europe “very grim”, with estimates that 150,000 Russian troops are posted around Ukraine’s borders.
But the Downing Street incumbent stressed before his departure to Bavaria that “diplomacy can still prevail” if western leaders unite to demonstrate to Moscow that it would face a “high price” for any incursion.
He said: “There is still a chance to avoid unnecessary bloodshed, but it will require an overwhelming display of western solidarity beyond anything we have seen in recent history.
“Allies need to speak with one voice to stress to (Russian) President (Vladimir) Putin the high price he will pay for any further Russian invasion of Ukraine.
“Diplomacy can still prevail.
“That is the message I will take to Munich today as we redouble our efforts to prevent a grave miscalculation, which would devastate Ukraine, Russia and the rest of Europe.”
Western allies have been given further cause for concern this week after intelligence reported that 7000 troops have arrived on the border in recent days, despite the Kremlin insisting it was withdrawing some military presence.
Field hospitals and pontoon bridges have also been spotted close to the divide between the two countries, with increased activity in the separatist-held area of Ukraine, including a strong explosion being reported in the centre of the city of Donetsk on Friday.
Russian President Vladimir Putin has insisted that large-scale military exercises with Belarusian forces close to the Ukrainian border are “purely defensive” and do not represent a threat to any other country.