Russian climate envoy Anatoly Chubais has become the highest-level official to reject Russian President Vladimir Putin’s war against Ukraine and has fled Russia, according to new reports.

“Chubais, the most senior official to cut ties with the Kremlin after the invasion of Ukraine, was one the few 1990s Russian reformers who survived throughout Putin’s presidency, although he had little influence in recent years,” The Washington Post reported. “Chubais was not a member of Putin’s dwindling inner circle of hard-line security and military chiefs, known as the siloviki, or men of power. But his departure underscores the alarm felt by many in Russia’s comfortable urban classes at Putin’s war and his mounting witch-hunt for traitors and ‘fifth columnists.’”

According to Russian News Agency TASS, Chubais has left Russia, and Kommersant newspaper published a picture of Chubais withdrawing money from an ATM in Istanbul. Bloomberg News, which first reported the news, says Chubais departed Russia over his opposition to Putin’s invasion of Ukraine.

“Chubais, 66, is one of the few 1990s-era economic reformers who’d remained in Putin’s government and had maintained close ties with Western officials,” Bloomberg reported. “Known as the architect of Russia’s 1990s privatizations, Chubais gave Putin his first Kremlin job in the mid-1990s and initially welcomed his rise to power at the end of that decade. Under Putin, Chubais took top jobs at big state companies until the president named him envoy for sustainable development last year.”

The news comes a week after Putin said that Russia will undergo a “self-purification” of “traitors” as Russian forces have continued to fail to make progress in the invasion of Ukraine.

“The Russian people will always be able to distinguish true patriots from scum and traitors and simply spit them out like a fly that accidentally flew into their mouths,” Putin said. “I am convinced that such a natural and necessary self-purification of society will only strengthen our country, our solidarity, cohesion and readiness to respond to any challenges.”