WASHINGTON—The U.S. Treasury Department on Thursday levied sanctions against several Iranian firms, individuals and officials it said are operating an illegal currency-exchange network in the United Arab Emirates, and accused Iran’s central bank of being complicit in operations that funneled dollars into the country for Iran’s elite military unit, the Quds Force, and Tehran’s regional proxies.
The action, the first since President Donald Trumppulled the U.S. out of the landmark nuclear deal with Iran and Washington began reimposing...