Ukraine has significantly increased Russian military losses in recent months, driven largely by the expanded use of combat drones, according to the Washington-based think tank Center for Strategic and International Studies (CSIS).
The report, published on Wednesday, said Russia has suffered an estimated 1.4 million military casualties - including troops killed, wounded or missing - since the start of its full-scale invasion in February 2022, compared with about 600,000 on the Ukrainian side.
CSIS estimated that between 400,000 and 450,000 Russian troops have been killed, compared with 125,000 to 150,000 Ukrainian military deaths. In January, the think tank had estimated Russian fatalities at about 325,000.
The report said the ratio of Russian to Ukrainian casualties, which had generally ranged between 2:1 and 3:1 during the war, rose to an estimated 8:1 in the first half of 2026 as Ukrainian drone warfare became more effective.
According to CSIS, Russia's monthly military losses now exceed the number of new recruits joining its armed forces.
The think tank said its estimates are based on information from military, intelligence and government sources in multiple countries. While CSIS is widely regarded as a credible research organization, casualty figures in the war cannot be independently verified, and both Russia and Ukraine are widely believed to understate their own losses while overstating those of their opponent.
The report also said Russia's military offensive has slowed. It said Russian forces failed to expand the territory under their control in the first half of 2026 for the first time in years and, in some areas, ceded ground to Ukrainian forces. Russian advances along the more than 1,000-kilometre front line have also slowed, it said.
