Federal prosecutors in the Southern District of New York on Tuesday announced criminal charges against Turkish state-run bank Halkbank in an alleged multibillion-dollar plot to help Iran evade U.S. economic sanctions.

The six-count indictment charged Halkbank with fraud, money laundering and sanctions offenses for its “systemic participation” in the massive scheme, which included designing fraudulent transactions meant to deceive U.S. regulators and foreign banks and then lying to cover up its involvement.