The assessment, which couldn’t be independently verified, could bolster Kyiv’s aim to drive up the cost for Moscow.
Despite heavy casualties, Russian forces have made little significant progress on the battlefield, according to the officials. Approximately 35,000 Russian soldiers were killed in December 2025, nearly twice NATO’s average monthly estimate for the year.
Ukrainian Defense Minister Mykhailo Fedorov has outlined a strategy to increase Russian losses to 50,000 troops per month by summer. Kyiv believes this level would make it difficult for Kremlin dictator Vladimir Putin to replace manpower without ordering an unpopular mobilization.
Western officials attribute the rising losses largely to Ukraine’s increasingly effective use of drones. In December, Russia’s losses roughly equaled its monthly recruitment numbers. But the January shortfall suggests Ukraine’s attrition strategy may be taking effect, though officials cautioned it remains unclear whether Ukrainian forces can sustain the pace.
At the current rate of advance, Russian troops could need up to two more years to fully capture Donetsk Oblast.
Earlier, President Volodymyr Zelenskyy stated that Russian casualties had reached a record 35,000 killed per month, compared with about 14,000 monthly last year. Despite mobilizing 40,000–43,000 people each month, Russia is losing up to 45,000 troops due to combat deaths, injuries and desertions.