"Even if you're on the ground, it's very difficult for you to count casualties," said Marina Miron, a postdoctoral researcher at King's College London.

The Ukrainian military says Russia’s military losses have topped 1 million, noting the huge price Moscow has paid for its 3-year-old invasion.

Military leaders and analysts alike are questioning whether any level of battlefield attrition can alter Russia’s efforts to occupy still more of Ukraine. Former Commander-in-Chief of the Armed Forces of Ukraine Valerii Zaluzhnyi admitted in November,