"Putin is the leader of an organised criminal gang," Yulia Navalnaya said.
Trouble stirs in Europe after French president Emmanuel Macron claimed the West would not rule out sending soldiers.
But the separatists stopped short of requesting to officially join Russia.
The late Kremlin critic also made a sad prediction for 10 years' time.
It's not just about what is happening on the frontline.
The UK's foreign secretary was not the only one to go in for a face-to-face confrontation with Sergei Lavrov at a G20 meeting on Wednesday.
The body of Vladimir Putin's longtime foe is being hidden, his mother alleged.
The invasion of Ukraine has left Russia pretty isolated on the world stage – not that the Russian president seems ready to acknowledge that.