Ammunition is exploding only at open storage areas of the Ukrainian Armed Forces arms depots near the town of Kalynivka, Vinnytsia region, Yuriy Biriukov, an adviser to the president of Ukraine and assistant to the defense minister, has said.

"Underground storages are unaffected, concrete hangars are unaffected, brick warehouses are unaffected. [Ammunition] at the open areas is exploding. Keeping ammunition in the open is not our invention, it's a common practice," Biriukov wrote on his Facebook page.