A fire on a farmland near the village of Maloyanysol, 45 km from Mariupol, spread to an arms depot nearby causing detonations, the Defence Ministry has said.
The explosions, which were first registered at 4.20 pm Kyiv time, stopped two hours later.
A firefighting tank was used to extinguish the fire.
Around 30 persons from private houses located in the area were evacuated.
A staff was set up to investigate the incident and deal with its consequences.