Mizintsev orchestrated the siege of the Ukrainian city of Mariupol in the early months of the war last year. In September, he was appointed deputy defence minister in charge of logistics and supplies.
Imposing sanctions against Mizintsev last June, the European Union referred to him as the Butcher of Mariupol and said he was responsible for the “inhuman” siege of the shattered Ukrainian city, which Russia says it is now rebuilding.
His departure was reported by a Russian military blogger, Alexander Sladkov, and by the RBC news site. Neither offered an explanation for why he had apparently been removed.
The defence ministry did not immediately respond to a request for comment, while the Kremlin has said it cannot say anything on the subject and has referred questions on the matter to the defence ministry.
Russia has seized more than a sixth of Ukraine’s territory, but has sustained heavy losses in the course of the 14-month war. It has achieved no significant gains since last July, while being forced into major retreats around the cities of Kharkiv and Kherson.
It is currently bracing itself for a Ukrainian counteroffensive, while trying to take full control of the city of Bakhmut in eastern Ukraine after months of grinding warfare.
President Vladimir Putin has frequently reshuffled top military figures without explanation, including in January when Valery Gerasimov, chief of the general staff, replaced Sergei Surovikin in overall charge of what Russia calls its “special military operation”.