Some 32,000 men who were recruited from Russian prisons for military service in Ukraine have returned home, private army Wagner chief Yevgeny Prigozhin said on Sunday.
They had fulfilled their contract and were deployed in the fighting, he said.
Women and human rights activists have expressed concern that so many criminals, including murderers and other violent criminals, were being pardoned and released back into Russian society prematurely.
In some cases, the convicted felons had already committed new murders.
But the Wagner boss sees military service as a great resocialization programme. Prigozhin claimed in a voice message published on his Telegram channel that those released had committed a total of only 83 crimes.
That is 80 times fewer crimes than those who were regularly released after serving their sentences.
Prigozhin, a close confidant of Kremlin leader Vladimir Putin, had recruited some of the prisoners himself in the prison camps. Those who signed a contract to fight in the war were pardoned by Putin. The condition was to complete at least six months of combat missions in Ukraine.
In March, Prigozhin said the number of released ex-prisoners from the Wagner ranks was 5,000. After the capture of the eastern Ukrainian town of Bakhmut, he said he lost 20,000 men in the fighting there, including 10,000 ex-prisoners.
In many cases, he worked to ensure that the criminals received a burial with military honours.
Human rights activists complain that Russia continues to recruit criminals en masse for military service in prisons. They say the Defence Ministry is now using the penal system to recruit fighters.
