Ukrainian President Volodymyr Zelenskiy said he discussed the weekend's turmoil in Russia in a phone call with U.S. President Joe Biden on Sunday and that the events had exposed the weakness of Russian President Vladimir Putin's rule.
"I spoke with US President Joseph Biden. A positive and inspiring conversation," Zelensky tweeted.
"We discussed the course of hostilities and the processes taking place in Russia," he said, adding the two had also discussed long-range weapons.
The White House confirmed the talks in a separate statement.
"The world must put pressure on Russia until international order is restored," Zelensky added.
An armed rebellion by Wagner chief Yevgeny Prigozhin, who had vowed on Friday to topple the Russian military leadership, sparked Russia's largest political crisis in decades.
At the weekend, Prigozhin ordered his forces to take over a key military headquarters in southern Russia and launch a march on Moscow, before suddenly telling his mercenaries to turn around after a deal with Belarusian President Alexander Lukashenko.
The aborted revolt has left many in Russia and abroad stunned.
Zelensky also said that the two leaders also discussed more US aid "with an emphasis on long-range weapons" and coordinated the two countries positions on the eve of a NATO summit in Vilnius next month.
He also discussed the crisis in phone conversations with Canadian Prime Minister Justin Trudeau sharing "Ukraine's assessments of the attempted coup in Russia and the impact of this situation on the course of hostilities".
And in a separate conversation with Polish President Andrzej Duda, they discussed the situation on the battlefield and the threat to the Zaporizhzhia nuclear plant, in southern Ukraine, held by Russian forces.
