The U.S. Treasury Department put sanctions on the son, nephew and brother of a man who allegedly runs a money laundering operation on behalf of organized criminals.

Treasury said it placed sanctions on the son, nephew and brother of Altaf Khanani, all of whom it said played roles in running the Altaf Khanani Money Laundering Organization. The organization, Treasury said in November when placing it under sanctions, launders money for organized crime groups, drug-trafficking organizations and terrorist groups throughout the...