AVDIIVKA, Ukraine — As the afternoon shadows grow long, nocturnal creatures begin to stir. A stray cat rises from a nap, stretches and trots off to hunt. Overhead, swallows swoop and screech in the deepening twilight.

Soon, the human inhabitants of this town in eastern Ukraine set about their evening rituals.

Green-clad soldiers strap on their helmets and load their guns, while white-clad European cease-fire observers pocket their notebooks, climb into their cars and drive away. And then the fighting starts.

This improbable routine between soldiers and monitors with the Organization for Security and Cooperation in Europe plays out nightly, illustrating the glum quagmire of the Ukraine war, now entering its third year.

“I never see them here at night,” said Tatyana Petrova, whose apartment looks over a parking lot that is a frequent listening post for the monitors. “In the evening, I look out and they are gone, and then the concert starts.”