Only one of the Ukrainian Army checkpoints encircling the separatist stronghold of Slovyansk, where a military operation was in its third day on Thursday, was letting traffic through — most on its way out.

Beyond it, the sporadic boom of heavy artillery shelling in the northern outskirts punctuated an eerie calm in the mostly unscathed center of the sun-drenched town, where residents on bicycles and pushing strollers weaved their way through rebel roadblocks of felled trees, sand bags and rusted cars.

Nobody jumped at the sound.