With hands still dirty from the battlefield, a dozen Russian prisoners of war sat, stony-faced, in a conference room of a Ukrainian news agency Saturday and described being captured after their armored columns were ambushed.

Lt. Dmitry Kovalensky, who had fought in a Russian tank unit and spoke at the behest of his Ukrainian captors, said he recently came under fire from an armed drone and shoulder-launched anti-tank missiles on a road near Sumy in northeastern Ukraine. "The whole column burned,” he said.

Around the same time and a few miles away, at a makeshift Ukrainian military base in an abandoned building on the western edge of Kyiv, Ukrainian soldiers prepared for the same sort of ambushes that took out Kovalensky’s unit.