Russia’s Defense Ministry nominated Air Force General Sergei Surovikin as the overall commander of Russian forces operating in Ukraine on Saturday, the third high military appointment in a week.

The reshuffle comes after the reported dismissal of the commanders of two of Russia’s five military regions earlier this week, as its forces have suffered a series of stunning losses in northeastern and southern Ukraine in recent weeks.

The ministry did not say who, if anyone, Surovikin was replacing.

British military intelligence said in April that General Alexander Dvornikov had been appointed to take charge of Russian forces in Ukraine, almost two months after Moscow began what it calls its “special military operation”, in an attempt to “centralise command and control”.

However, Moscow itself has not specified that anyone is in overall military command of the operation.

Surovikin, 55, has led Russia’s Air and Space Forces since 2017. According to the ministry’s website, he commanded a guards division stationed in Chechnya in 2004, during Moscow’s war against Islamist rebels, and was awarded a medal for his service in Syria in 2017.