WASHINGTON: A declassified US intelligence report assessed that the Ukraine war has cost Russia 315,000 dead and injured troops, or nearly 90% of the personnel it had when the conflict began, a source familiar with the intelligence said on Tuesday.

The report also assessed that Moscow’s losses in personnel and armored vehicles to Ukraine’s military have set back Russia’s military modernization by 18 years, the source said.

The Russian embassy and the Russian defense ministry did not immediately respond to requests for comment.

Russian officials have said Western estimates of Russian death tolls in the war are vastly exaggerated and almost always underestimate Ukrainian losses - which Russian officials say are vast.

The source spoke as Ukrainian President Volodymyr Zelenskiy made a last-ditch plea to US lawmakers on Capitol Hill to keep US military aid flowing to Ukraine, first meeting behind closed doors with US senators.

Two killed in Russian attack on Ukraine’s Kherson

The source said the recently declassified US intelligence report assessed that Russia began its full-scale invasion of Ukraine in February 2022 with 360,000 personnel.

Since then, the report found, 315,000 Russian troops, or about 87% of the total with which it started the war, have been killed or injured, the source said.

The source said those losses are the reason Russia has been forced to loosen recruitment standards and draft convicts and older civilians to deploy in Ukraine.

“The scale of losses has forced Russia to take extraordinary measures to sustain its ability to fight. Russia declared a partial mobilization of 300,000 personnel in late 2022, and has relaxed standards to allow recruitment of convicts and older civilians,” the assessment said, according to the source.

The Russian army has been left with 1,300 armored vehicles on the battlefield and is having to bolster those forces with T62 tanks produced in the 1970s, the source said.

Kyiv treats its losses as a state secret and officials say disclosing the figure could harm its war effort. A New York Times report in August cited US officials as putting the Ukrainian death toll at close to 70,000.

Writing in the Ukrainian journal Tyzhden, historian Yaroslav Tynchenko and volunteer Herman Shapovalenko last month said Shapovalenko’s Book of Memory project had confirmed 24,500 Ukrainian combat and non-combat deaths using open sources.

The real figure was likely higher, they said.