A gigantic, roiling cloud of black smoke swirled up from a parking lot of burning cars, as residents milled about on a sidewalk in distress, and police and fire vehicles careened past. Then the scene became more chaotic.

“Shelter! shelter!” a policeman yelled. A thin, buzzing noise, like a chain saw running in the distance, wafted down from the sky. Another Russian exploding drone, like the one that had just hit the parking lot, was flying overhead. People ran for cover.

“It’s like this every day,” said the mayor, Artem Kobzar, who had been visiting the site in Sumy, Ukraine, and dashed into the open doorway of an apartment building. “Everybody in Ukraine wants peace,” he said. “But you see, in Sumy, we don’t have a day or night of calm.”

That bombardment came on Monday, a day after two ballistic missiles struck a central neighborhood of the city on Palm Sunday shortly after 10 a.m., killing 34 civilians, including two children, and wounding another 117, according to the Sumy City Council. Russia said it had struck a military target; a Ukrainian regional governor said a military awards ceremony had taken place in the city that day.

The Palm Sunday bombardment came more than two months after President Trump started cease-fire talks with a phone call to President Vladimir V. Putin of Russia. And in recent days it has become an argument in Ukraine and elsewhere that those talks are failing. In Sumy, the attack has set off preparation for a possible new Russian ground assault in this region.