Yevgeny Prigozhin, founder of Russia's Wagner Group mercenary force, published a video on Saturday showing what he said were coffins containing bodies of Ukrainian soldiers being repatriated to territory held by Kyiv.
In the video, Prigozhin, clad in full military gear, said: "We are sending another shipment of Ukrainian army fighters home. They fought bravely, and perished. That's why the latest truck will take them back to their motherland."
The footage shows men in uniform nailing wooden coffins shut and loading them onto a truck.
Prigozhin, whose Wagner Group has spearheaded Russia's months-long assault on the eastern city of Bakhmut, has repeatedly praised the Ukrainian army as a worthy and capable adversary.
On New Year's Eve, a media outlet linked to Prigozhin published footage of the Wagner boss visiting Ukrainian prisoners of war with a traditional gift of mandarins, and promising to return them to Ukraine via a prisoner swap as soon as possible.