US moves to end the war in Ukraine could work in Russia's favour, according to one expert.

President Donald Trump says talks will start immediately - and he's had a phone call with Russian President Vladimir Putin.

Commentators say it's highly unlikely Ukraine will get back its pre-war borders - a bottom line for leader Volodymyr Zelenskyy.

Canberra law professor Sascha Dov Bachmann says Putin will tell his people any territory Russia takes is a win.

"And that is the dangerous thing, that is the first step in the wrong direction." 

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