Russian billionaire Oleg Deripaska, long facing scrutiny over his ties to President Vladimir Putin, on Friday sued the U.S. government to reverse “devastating” sanctions that he claimed have destroyed his reputation and cut him off from international business.

Deripaska, represented by Washington lawyer Erich Ferrari, who specializes in U.S. government sanctions disputes, claimed U.S. Treasury’s block on his property and assets have contributed to the “wholesale devastation of [his] wealth, reputation, and economic livelihood.” Deripaska’s suit claimed he has lost $7.5 billion since the Treasury first imposed sanctions in April 2018.