Russia has been accused of risking European peace with its “Cold War demands” over Ukraine, as the US scoffed at claims Moscow was withdrawing its troops.

“With an unprecedented deployment of troops on the border with Ukraine and Cold War demands, Russia is challenging fundamental principles of the European peace order,” German Foreign Minister Annalena Baerbock said on Friday (Australian time), ahead of the annual Munich Security Conference.

The Russia-Ukraine tensions are expected to be high on the conference’s agenda, with US Secretary of State Antony Blinken due to meet his European counterparts.

Earlier, the US accused Russia of a “ruse” over its claims it was pulling troops out of its tense border region with Ukraine. US officials said on Friday that evidence from the region showed Russia was instead “moving towards an imminent invasion”, despite Moscow’s repeated claims.

The allegations came as Ukraine and Russian-backed separatists each accused the other of violating a ceasefire, with a kindergarten in disputed Ukraine territory on the Russian border shelled on Thursday. Hours later, the Interfax news agency in the same region of the self-proclaimed Donetsk People’s Republic said the village of Petrivske had been targeted in artillery and mortar attacks.

The Kremlin said on Thursday it was “deeply concerned” with the flare-up in Ukraine and was watching the situation closely.

Tensions remain high in the disputed border region, where Kyiv’s forces and pro-Russian separatists have been at war for years.

Earlier, US President Joe Biden accused Russia of creating excuses to justify an attack on its neighbour “within days”.

“We have reason to believe they are engaged in a false-flag operation to have an excuse to go in,” Mr Biden said at the White House.

“Every indication we have is they’re prepared to go into Ukraine and attack Ukraine.”

He ordered Mr Blinken to change his travel plans to speak at a United Nations Security Council meeting, where he outlined possible Russian scenarios.

“It could be a fabricated so-called terrorist bombing inside Russia, the invented discovery of a mass grave, a staged drone strike against civilians, or a fake – even a real – attack using chemical weapons,” Mr Blinken said.

“Russia may describe this event as ethnic cleansing, or a genocide.”

Russia’s Deputy Foreign Minister Sergei Vershinin said Mr Blinken’s comments were regrettable and dangerous.

Diplomatic efforts were also continuing, with Mr Biden to host a call with the leaders of Canada, France, Germany, Italy, Poland, Romania, Britain, the European Union and NATO in coming hours.

Mr Blinnken would also discuss the crisis late next week with Russian foreign minister Sergei Lavrov, “provided there is no further Russian invasion of Ukraine”, the State Department said.

But in a blow to US-Russian relations, Russia has expelled the US’s second-highest ranking diplomat, Deputy Chief of Mission Bart Gorman.

The move was announced on Thursday (US time) but a senior State Department official said Mr Gorman left last week. He is now back in the US.

“We consider this an escalatory step and are considering our response,” a US State Department spokesman said.

Moscow cited the US expulsion of one of its senior officials in Washington, who it said was forced to leave before a replacement could be found as part of a US “visa war”. Washington said it would respond to the “unprovoked” move.

In Ukraine, government forces denied accusations of having targeted separatist positions in the breakaway region. Details could not be established independently, but reports from both sides suggested an incident more serious than the routine ceasefire violations that are common.

Russia has long said Kyiv wants an excuse to seize rebel territory by force, which Ukraine denies.

Ukraine’s President Volodymyr Zelenskiy said the pro-Russian forces had shelled a kindergarten, in what he called a “big provocation”.

Video footage released by Ukrainian police showed a hole through a brick wall in a room scattered with debris and children’s toys.

The separatists, for their part, accused government forces of opening fire on their territory four times in the past 24 hours.

Estimates also vary about how many Russia soldiers have massed near Ukraine. Nearby NATO member Estonia cited about 170,000 troops earlier this week.

The White House said Russia had added 7000 troops to border positions in just 24 hours.

On brink of ‘all-out conflict’

Defence Minister Peter Dutton says a Russian invasion of Ukraine is imminent, indicating the nation is on the cusp of an “all-out conflict”.

Mr Dutton told the Nine Network on Friday there were multiple signs an attack would happen soon.

“It’s tragic and we’ll see terrible scenes unfolding,” he said.

“You would expect that President [Vladimir] Putin, who obviously can’t be taken at his word, is manufacturing some sort of trigger, or is in the process of executing the final stages of his plan to go into Ukraine.”

Mr Dutton said while European leaders had attempted to prevent a conflict in Ukraine, President Putin was intent on military action.

“That really is going to result in the loss of innocent life,” he said.

“We’ve seen it before in eastern Europe. We don’t want it repeated but we live in a very uncertain world.”

The head of Ukraine’s diplomatic mission in Australia, Volodymyr Shalkivskyi, said even if there was no invasion, the effect on the nation would be detrimental.

“Two, three or five months of such pressure will be devastating for our economy,” he told the Australian Strategic Policy Institute.

“It’s my personal opinion that Mr Putin has enough resources to wait for months, for years, keeping pressure on Ukraine and waiting for the perfect timing.”

Despite the pressure from Russia, Mr Shalkivskyi said Ukraine should still join NATO.

-with AAP