During the call, which Trump took from his resort in Florida, he advised the Russian president not to escalate the war in Ukraine and reminded him of Washington’s sizable military presence in Europe, said a person familiar with the call, who, like others interviewed for this story, spoke on the condition of anonymity to discuss a sensitive matter.

As Donald Trump's election win brings the prospect of talks to end Russia's war in Ukraine closer, Kyiv is battling to put itself in the strongest position for any negotiations, including by securing more arms and holding out on the battlefield.