Ukrainian President Volodymyr Zelenskiy on Thursday urged minority groups across Russia to resist the Kremlin's mobilisation effort, telling them they need not die in a "shameful war".
Zelenskiy made the remarks in a video appeal on the eve of a Kremlin ceremony to mark the annexation of four Ukrainian regions occupied by Russian forces.
Non-Russian groups - mainly from the Caucasus in the south of Russia and from Siberia - are over-represented in military contingents sent to Ukraine and violent protests against the mass mobilisation have erupted in some areas gripped by poverty.
"You don't have to die in Ukraine. Your sons don't have to die in Ukraine," Zelenskiy said, standing next to a monument in Kyiv to an imam from the Caucasus.
He said Russia had been isolated by a war sought solely by President Vladimir Putin who "will not stop" at the first wave of mobilisation.
"There will be more. He will try to take even more lives... no one is obliged to take part in a shameful war."
According to publicly available data on military casualties compiled by Russian investigative outlet iStories, soldiers from Buryatia, on the border with Mongolia, and Dagestan, a mainly Muslim area on the Caspian Sea, have suffered the highest casualty rate in the conflict.
More than 100 people were detained in protests in Dagestan against the draft last week.