According to the White House, 100,000 Russians have perished in the Ukraine conflict since December, including 20,000 of its fighters.
The most recent statistics coincide with an uptick in bloodshed in the nation as Kyiv gears up for a counteroffensive to drive the invaders out of territory they earlier this spring.
The eastern half of the annexation of Donbas, where the Kremlin’s men are still battling to encircle Bakhmut after months of Ukrainian resistance, has seen the most violent fighting.
White House National Security Council spokesman John Kirby said the US estimate is based on newly declassified American intelligence.
He did not detail how the intelligence community derived the figures.
They would suggest, however, that Russian losses have accelerated dramatically in recent months.
In November last year, chairman of the Joint Chiefs of Staff General Mark Milley said well over 100,000 Russians had been killed or wounded since they invaded Ukraine the previous February.
If accurate, the new numbers from the US would suggest the country has reached the same grim milestone in five months as it previously did in eight.
Mr Kirby said almost half of the fighters lost by Russia since December were Wagner forces, many of whom are convicts released from prison specifically to enter combat.
He described the forces under Wagner command as being ‘thrown into combat and without sufficient combat or combat training, combat leadership, or any sense of organisational command and control’.
In particular, he highlighted the shocking toll for the ‘little town of Bakhmut’, which he compared to some of the bloodiest periods of fighting in the Second World War.
Mr Kirby said: ‘It’s three times the number of killed in action that the United States faced on the Guadalcanal campaign in World War Two and that was over the course of five months.’
He declined to give a figure for Ukrainians killed and wounded, though General Milley said in November that Kyiv had also suffered around 100,000 casualties.
The Kremlin claimed to have dented Ukraine’s imminent counteroffensive in missile strikes this morning, destroying ammunition supplied by the West and hitting key communication links.
Russian defence ministry spokesman Lt-Gen Igor Konashenkov said this morning: ‘As a result of an attack on a train at a railway station near the settlement of Kramatorsk in Donetsk People’s Republic up to 200 tons of Ukrainian ammunition supplies were eliminated.’
One person died in the Kherson region and 34 people – including five children – were injured in Dnipropetrovsk, it was reported.
Two women were also in intensive care, the Dnipropetrovsk RMA said, following the second incident of pre-dawn violence in three days.