Russia’s Black Sea fleet based in annexed Crimea has installed a new commander, RIA news agency cited sources as saying on Wednesday, after Russian military bases on the peninsula were rocked by explosions in the past nine days.

If confirmed, the removal of the previous commander Igor Osipov would mark the most prominent sacking of a military official in the nearly six months since Russia launched its war on Ukraine, in which it has suffered heavy losses in men and equipment.

State-owned RIA cited the sources as saying the new chief, Viktor Sokolov, was introduced to members of the fleet’s military council in the port of Sevastopol.

One source said it was “normal” that the appointment was not publicly announced at a time when Russia is conducting what it calls its “special military operation” in Ukraine.