Anatoly Chubais speaks in Moscow, Russia, in October 2019.
CNN  — 

Anatoly Chubais, a Russian government insider for decades, is leaving his job as President Vladimir Putin’s special representative on the environment, Russian state news agency TASS reported Wednesday, citing an unnamed source.

Chubais quit his post as a Kremlin special envoy and left the country due to the war in Ukraine, according to Reuters, which cited two sources familiar with the matter. Chubais did not immediately respond to CNN’s request for comment. He has not independently confirmed that he has left Russia or the reason for his resignation.

Chubais had been in the environment job since December 4, 2020, TASS said.

He rose to prominence as Boris Yeltsin’s finance minister in the 1990s.

According to Reuters, Chubais was considered by his opponents to be responsible for the selling of state-owned assets to a small group of oligarchs after the fall of the Soviet Union. Many of those oligarchs have been placed under Western sanctions since the start of the war in Ukraine.

However, his supporters credit Chubais’s attempts to transition Russia’s economy into a free market.

In the early days of Putin’s rise to power, Chubais was considered an opponent by the now-president. Putin claimed in a series of interviews in 1999 that Chubais canceled the Kremlin job that he was initially offered.

In recent years, Chubais continued to call for economic reform and was one of the most high-profile liberals associated with the Russian government.