In his new clothes store in the heart of Ukraine's front-line city of Kramatorsk, Maksym Lysenko suddenly stops talking and listens. "There," he says, leaning towards the window looking onto the street. "It's going to dive. Lysenko has heard the high-pitched whine of a Russian suicide drone. It's the third attack witnessed by Reuters in less than an hour by Russian kamikaze drones terrorizing the skies over one of Ukraine's final bastions in the fiercely contested region of Donetsk.