The build-up of Russian military forces on Ukraine's border matters to Australia despite being half a world away, US Secretary of State Antony Blinken says.
Following talks in Australia as part of the Quad strategic partnership, Mr Blinken said the United States would maintain its dual-track approach to Russia and the forces it has amassed at the border "unprovoked".
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 told reporters in Melbourne on Friday after Quad talks wrapped for the day.
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 a hard-fought play after two world wars, and a cold war - undergirded security, peace and prosperity for countries around the world.
"Principles like one country can 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 an interview with Nine newspapers, Mr Bilken said he would expect Australia to play its role in imposing "massive costs" on Moscow should it invade.
He said the US and its allies were still ironing out what that would entail, but floated the prospect of economic and financial sanctions, export controls, and building up Ukraine's armed forces and NATO defences.
In the meeting with her 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."
