Oleksii Yukov spends many of his nights dodging drones, navigating minefields and hoping not to be targeted by Russian artillery as he races to collect the remains of fallen soldiers from the battlefield.

In just three shattered tree lines around the ruined village of Klishchiivka outside Bakhmut, where Ukrainian and Russian forces have fought seesaw battles for well over a year, he collected 300 bodies. They were almost all Russian, he said, left behind in maelstrom of violence where the struggle to stay alive often outweighs concern for the dead.

Mr. Yusov has been collecting bodies from the bloody fields and battered villages of eastern Ukraine for a decade. He is now the head of a group of civilian volunteers called Platsdarm, and has witnessed more death than he would care to remember.

But as Russia presses a slow-moving offensive at great human cost, Mr. Yusov says the toll is still shocking.