Kyiv. The number of soldiers killed, injured, or missing on both sides of Russia's war on Ukraine could be 2 million by spring, with Russia sustaining the largest number of troop deaths for any major power in any conflict since World War II, a report warned Tuesday.

The report from the Center for Strategic and International Studies came less than a month before the fourth anniversary of Moscow's full-scale invasion of Ukraine on Feb. 24.

The CSIS report said Russia suffered 1.2 million casualties, including up to 325,000 troop deaths, between February 2022 and December 2025.

“Despite claims of battlefield momentum in Ukraine, the data shows that Russia is paying an extraordinary price for minimal gains and is in decline as a major power,” the report said. “No major power has suffered anywhere near these numbers of casualties or fatalities in any war since World War II."

It estimated that Ukraine, with its smaller army and population, had suffered between 500,000 and 600,000 military casualties, including up to 140,000 deaths.

Neither Moscow nor Kyiv gives timely data on military losses, and each side seeks to amplify the other side’s casualties.

Commenting on the report, Kremlin spokesperson Dmitry Peskov said Wednesday that the research could not be considered “reliable information” and that only Russia’s Ministry of Defense was authorized to provide information on military losses.

The ministry has not released figures on battlefield deaths since a statement in September 2022 that said just under 6,000 Russian soldiers had been killed.

The Ukrainian government had no immediate comment on the report. In an interview with NBC in February 2025, Ukrainian President Volodymyr Zelenskyy said that more than 46,000 Ukrainian soldiers had been killed since the war began.

The CSIS report estimated that at current rates, combined Russian and Ukrainian casualties may be as high as 1.8 million and could reach 2 million by spring.

The figures from the CSIS were compiled using the Washington-based think tank’s own analysis, data published by independent Russian news site Mediazona with the BBC, estimates by the British government, and interviews with state officials.

A War of Attrition
Reports about military losses have been repressed in Russian media, activists and independent journalists say.

Mediazona, together with the BBC and a team of volunteers, has so far collected the names of more than 160,000 troops killed by scouring news reports, social media, and government websites.

The report also said Russian forces were advancing at a sluggish pace since they seized the initiative on the battlefield in 2024, despite their much larger size.

Russia’s advance in Ukraine has largely settled into a grinding war of attrition, and analysts say Russian President Vladimir Putin is in no rush to find a settlement, despite his army’s difficulties on the roughly 1,000-kilometer (600-mile) front line.

The report said Russian forces have advanced at an average rate of between 15 and 70 meters (49 to 230 feet) per day in their most prominent offensives.

That is “slower than almost any major offensive campaign in any war in the last century,” the report said.

Putin told his annual news conference last month that 700,000 Russian troops are fighting in Ukraine. He gave the same number in 2024, and a slightly lower figure — 617,000 — in December 2023. It was not possible to verify those figures.