Russian President Vladimir Putin relieved Dmitry Kozak of his duties as deputy head of the presidential administration, a presidential decree published on the Kremlin website said on Thursday.
The news was first reported by Russian outlet RBC on Wednesday, citing two sources who said Kozak resigned "of his own free will" to pursue business interests.
However, in analysis from the Institute for the Study of War (ISW) that was then reproduced in other publications, the U.S. military think tank alleged that Kozak was pushed out by senior Kremlin officials for his disagreements with Putin on the Ukraine conflict, "likely" with Putin's personal approval.
While it cannot be independently confirmed whether Kozak was driven out or resigned on his own volition, a report in the New York Times last month stated that the official had privately advised Putin against Russia's invasion of Ukraine in 2022 and had since pushed for initiatives to end the conflict.
According to the Times, Kozak also pushed for a number of domestic reforms such as increasing the independence of the judiciary and increasing the oversight of Russia's security services. All in all, the moves led to a loss of influence with much of his responsibilities being shifted to another top aide, Sergei Kiriyenko, the publication further reported.
Though it was then the Soviet Union, Kozak was born in the Ukrainian region of Kirovohrad in 1958. He went on to study law in St Petersburg — then known as Leningrad — before working in its city hall in the 1990s. That's where he met Putin who brought him into government when the latter became president in 2000.
Kozak resigned his post on his own free accord, and this was subsequently accepted by Putin — as ultimately confirmed in the presidential decree issued later in the day.
Kozak was most likely pushed out for being the sole voice that was willing to challenge Putin's increasingly hardline on Ukraine, as well as other domestic matters.