Ukrainian President Volodymyr Zelenskyy discussed the Wagner Group mutiny in Russia with several world leaders on Sunday.
Zelenskyy said he and US President Joe Biden "discussed the course of hostilities and the processes taking place in Russia" among other things.
"Yesterday's events exposed the weakness of Putin's regime," he added.
Earlier, Zelenskyy had a phone call with Polish President Andrzej Duda.
"We discussed the latest developments in Russia and how they could affect the course of hostilities and the security situation in the region," he said.
"I told him about the situation on the battlefield and the threatening situation created by the occupiers at the Zaporizhzhia Nuclear Power Plant."
Zelenskyy also spoke with Canadian Prime Minister Justin Trudeau about the impact of the Russian unrest, as well as the upcoming NATO summit in Vilnius, Lithuania.
Australia provides Kyiv with $73.5 million package
The Australian government will provide an aid package of 110 million Australian dollars ($73.5 million, €67.4 million) to Ukraine, Prime Minister Anthony Albanese says.
The package is to include 28 M113 armored vehicles, 14 special operations vehicles, 28 medium trucks and 14 trailers.
"Australia is unwavering in our resolve to condemn and oppose Russia's actions and to help Ukraine achieve victory," Albanese said.
Australia will also extend duty-free access for goods imported from Ukraine for an additional 12 months.
This brings Australia's contribution to Ukraine up to around €489 million, most of which has been made up of military assistance.
Over 17,000 Ukrainian recruits trained by UK-led program — ministry
More than 17,000 Ukrainian army recruits have been trained by the UK and other allies over the past year, the British Defense Ministry says.
The ministry said that recruits went through a "grueling" program, called Operation Interflex, that lasted five weeks.
Canada, Australia, New Zealand, Norway, Finland, Sweden, Denmark, Lithuania and the Netherlands were also involved in the initiative.
"The determination and resilience of the Ukrainian recruits that arrive on British soil, from all walks of life, to train to fight alongside our British and international forces, is humbling to witness," UK Defense Secretary Ben Wallace said.
"The UK and our international partners will continue to provide this vital support, helping Ukraine defend against Russian aggression, for as long as it takes."
The program has been extended and is to train some 30,000 recruits by 2024, according to British authorities.
EU foreign ministers to discuss Ukraine aid
European Union foreign ministers will meet in Luxembourg on Monday to discuss how to further support Ukraine.
The ministers are expected to increase the joint military aid fund by €3.5 billion ($3.85 billion).
Ukrainian Foreign Minister Dmytro Kuleba will join the meeting via video link.
The unrest in Russia over the weekend prompted German Foreign Minister Annalena Baerbock to shorten a planned trip to South Africa so she could attend the meeting.
Ukraine's defense minister: Russia should focus on its own problems
Ukrainian Defense Minister Oleksii Reznikov discussed the aftermath of the Wagner rebellion on a call with US Defense Secretary Lloyd Austin on Sunday.
"We agree that the Russian authorities are weak and that withdrawing Russian troops from Ukraine is the best choice for the Kremlin," Reznikov wrote on Twitter. "Russia would be better served to address its own issues."
He said they also discussed Ukraine's counteroffensive and ways to further help Ukraine's armed forces.
