KIEV, Ukraine — One of the Ukrainian Army’s largest ammunition depots caught fire overnight after what was probably an act of sabotage using a drone, an official said on Wednesday, setting off gigantic explosions and forcing the evacuation of about 30,000 people.

Like a lethal fireworks display, rocket artillery and tank shells flew out of the depot in all directions, tracing glowing arcs through the night sky and illustrating — if a drone is indeed to blame — the growing role of the devices in combat.

The blasts, in the town of Vinnytsya, about 160 miles southwest of Kiev, posed a serious danger to air traffic, passing trains and nearby communities.