Out on the riverbank, the scene of mayhem unfolded under a baking spring sun: blown-up tanks, the detritus of pontoon bridges, heaps of branches shorn off by explosions and the bodies of Russian soldiers, some half buried in the mud.

In the forest, a short walk revealed bits of torn Russian military uniforms hanging from trees, an eerie reminder of the troops who died violently here.

The failed river crossing that took place at this spot over several days in early May was one of the most lethal engagements of the war for the Russian army. Its forces had sought to surround Ukrainian soldiers in the nearby town of Sievierodonetsk — but instead became surrounded themselves, boxed in by the river and a Ukrainian front line. At least 400 Russian soldiers died, mostly from artillery attacks.