Prime Minister Scott Morrison says Australian citizens in Ukraine should leave the country as soon as possible as the situation there is increasingly dangerous.

“Our advice is clear, this is a dangerous situation … you should seek to make your way out of Ukraine,” Mr Morrison said in Sydney on Saturday.

He said the federal government first began warning Australians in the troubled eastern European nation to “put themselves in a position of safety” late last year.

“We have continued that, well into last month and it has been a clear message for some time now, that Australians in Ukraine should be seeking to get out of the country,” Mr Morrison said.

While their decisions were respected, the Prime Minister said the government’s advice was “very clear”.

His comments come after US Secretary of State Antony Blinken, who left Australia on Saturday, said Russia could invade Ukraine at any time and Washington and other countries urged their citizens to leave.

Following talks as part of the Quad strategic partnership, Mr Blinken said the US would maintain its dual-track approach to Russia and the forces it has amassed at the border “unprovoked”.

Deterrences and defences

That strategy involves the US keeping diplomatic dialogue open, while also building deterrences and defences if Russia chooses to invade.

“(We’ve been) making it clear to Russia that if it chooses the path of renewed aggression, it will face massive consequences,” Mr Blinken said on Friday.

An estimated 4000 foreign fighters, including Australians, have joined Ukraine’s militias and regular armed forces. Numbers are likely to boom if Russia invades.

Even though the conflict is brewing across the other side of the globe, Mr Blinken said what happens in Ukraine matters in Australia and the Indo-Pacific region, in an apparent reference to China.

“What’s at stake is not simply, as important as it is, Ukraine’s territorial integrity. It’s sovereignty, it’s independence,” he said.

“But very basic principles that have been hard fought for after two world wars, and a cold war: undergirded security, peace and prosperity for countries around the world.

“Principles like one country can’t simply change the borders of another by force. Principles like one country can’t simply dictate to another its choices, its policies, with whom it will associate.

“If we allow those principles to be challenged with impunity, even if it’s half a world away, that will have an impact here as well. Others are watching. Others are looking to all of us to see how we respond.”

In Friday’s Quad meeting with counterparts from the US, India and Japan, Foreign Minister Marise Payne said she reiterated her “very deep concerns” about the presence of Russia’s military on the Ukrainian border.

“We will continue to support our allies and partners to deter this sort of aggression and to raise the costs of this kind of behaviour.”

-AAP