In the quiet hours, they talked, ate and made sinister jokes.

“Who were you before the war?” one soldier asks another in a video shared by the brigade. “A fireman,” the other soldier replies. “I used to save people, but now I kill them.”

The fighting resumed on the third morning at 5 a.m.

The New York Times viewed video footage that the Ukrainian military said was taken by soldiers in battle that day and confirmed its location. It shows armored vehicles bursting through the first line of defense under a hail of gunfire. Infantry soldiers jump out, firing as they exit the vehicle.

“Go around the left side, you’re the first,” a soldier orders in one video. “Go!”

At this point, soldiers said, the only way to clear out the Russians was to go trench by bloody trench, unsure whether the Russians had fled, were hiding or were still fighting.

“Approaching! Move in!” one soldier shouts as they storm a Russian dugout. Something explodes near the Ukrainians. “Go! Go back!” another soldier yells.

The Ukrainians then approach the Russian dugout again and toss in a grenade, and it goes quiet, according to video footage.