Hundreds of Russian prisoners are reportedly being offered a pardon and released from jail to fight in the Russia-Ukraine war.
Russia's invasion of Ukraine has been ongoing for 170 days - since February 24 - in what Moscow calls a "special military operation".
Russia has been struggling to replenish troops with the army reportedly suffering about 80,000 casualties in the war - but Moscow denies this figure.
"It's safe to suggest that the Russians have probably taken 70 or 80,000 casualties in less than six months," Colin Kahl, a US Department of Defense undersecretary for policy, said at a briefing on Monday.
"That is a combination of killed in action and wounded in action and that number might be a little lower, a little higher, but I think that's kind of in the ballpark."
Drug offenders and murderers are now being recruited from prison - some even from where high-profile US Paul Whelan is held - in Russia's newest recruitment scheme, according to CNN.
Dozens of chat messages between relatives reportedly detailed the enticing rewards offered to fight in Ukraine, according to the US broadcaster.
"They will accept murderers but not rapists, paedophiles, extremists or terrorists," one prisoner told CNN from his jail cell.
"Amnesty or a pardon in six months is on offer. Somebody talks about 100,000 (NZ$2490) roubles a month, another 200,000. Everything is different."
The head of a prisoner advocacy group told CNN they have been flooded with reports from across Russia from anxious relatives, concerned about the fate of their inmates.
"In the last three weeks (in July), there is a very big wave of this project to recruit thousands of Russian prisoners and send them to the war," Vladimir Osechkin, head of Gulagu.net said.
Some inmates have been promised a pay-out to their families of five million rubles (NZ$124,000) if they died but the financial rewards are not certain.
"There is no guarantee, there's no real contract. It is illegal," Osechkin said.
Yevgeny Prigozhin, commonly known as "Putin's chef", is believed to have personally reached out to many inmates.
"They are primarily interested in murderers and robbers, they treat the drug addicts warily, the same with the rapists. It's better, he said, for it to not be common killers, but straight up calculating ones - you will like it with us, he said.
"In general, he gave the impression of a maniac," said one unnamed inmate quoted by Mediazona, an independent media outlet in Russia.
Prigozhin allegedly told inmates at an exile colony in Rybinsk that "World War III" was underway and was offering them the chance to fight for Russia, according to the inmate to Mediazona.
"Your decision to serve in the (private military company) is a deal with the devil. If you leave here with me, you will either return a free man or you will die.
"You will be required to kill enemies and follow the orders of leadership. Those who retreat will be shot on the spot," the inmate quoted Prigozhin as saying.
