UK prime minister Boris Johnson has issued a dire warning about what Russia might have in store as intelligence points to an imminent Ukraine invasion.
Speaking to the BBC from Munich after a security conference, Mr Johnson said Russia was preparing for the biggest conflict since World War II.
"The plan that we're seeing is for something that could be really the biggest war in Europe since 1945," he said.
The prime minister said, according to intelligence, Russia was not only planning an invasion through Donbas in southeastern Ukraine, but have forces encircle the capital of Kyiv.
Mr Johnson added: "I think people need to understand the sheer cost in human life that that could entail and not just for Ukrainians, but also for Russians."
The prime minister also told the BBC there were signs the plan had already begun "in some senses".
Earlier, after weeks of saying the US wasn’t sure if Russian president Vladimir Putin had made the final decision to launch a widespread invasion, Joe Biden said that assessment had changed, citing his country's "significant intelligence capability".
"As of this moment I'm convinced he's made the decision," Biden said.
"We have reason to believe that."
Biden reiterated it could occur in the "coming days".
Tensions continue to flare in Ukraine
Over the weekend, the Ukrainian military confirmed two soldiers were killed and four were wounded in a shelling, carried out by pro-Russian separatists.
The incident happened in east Ukraine, where there has been a flare up in violence over the week, sparking fears this could be the trigger for Russian military action.
The Ukrainian military said on its Facebook page it had recorded 70 ceasefire violations by separatists since the start of Saturday (local time) compared with 66 cases over the previous 24 hours.
Separatists opened fire on more than 30 settlements along the front line using heavy artillery, which has been prohibited by agreements aimed at cooling the long-running conflict, the military said.
A spokesperson for President Volodymyr Zelenskiy's party said in a statement on Saturday a group of lawmakers and foreign media visiting the conflict zone came under fire and had to be evacuated.
On Telegram, a social media site, separatists accused Ukraine of shelling separatist-controlled areas and said their attack was in response.
Incidents of shelling across the line dividing government forces and separatists increased sharply this week, in what the Ukrainian government called a provocation.
It strongly denied suggestions by Russia that Kyiv could launch an offensive in eastern Ukraine.
Do you have a story tip? Email: email@example.com.