In Dobropillia, a coal-mining town just a few kilometres from the front line with Russia in Ukraine's eastern Donbas region, its few remaining inhabitants shuffle to find food or water under the constant gaze — and hum — of the drones that now rule the battlefield.

The fierce battle for control of Pokrovsk has become a flashpoint in the war, with Zelensky vowing that Ukrainian forces will be “waiting” for Putin if he enters the city—an ominous signal of desperat...