A senior Russian naval official has been killed in Ukraine, according to authorities in the Crimean peninsula, marking the country’s sixth high-ranking military leader to fall since the invasion began nearly a month ago. Andrei Paliy, a 51-year-old commander in Russia’s Black Sea Fleet, died in battle for the key Ukrainian port city of Mariupol, the governor of Sevastopol said Sunday. Paliy was born in Kyiv but reportedly renounced allegiance to Ukraine after the fall of the Soviet Union, moving instead to Russia and enlisting in the navy. He was stationed at Sevastopol in Crimea, a region annexed by Moscow from Ukraine in 2014, as part of Russia’s Black Sea Fleet. His death was first reported over Russian social media by his former colleagues, according to The Telegraph. Konstantin Tsarenko, who once worked alongside Paliy at Sevastopol’s Russian Naval School, wrote on social media platform VKontakte that Paliy had been killed. His post was later deleted, but an ex-naval officer, Igor Savostin, wrote on the same site that Paliy had died “like a true commissar by leading the marines into battle.” Neither the Russian navy nor the defense ministry immediately confirmed Paliy’s death.