NEW YORK, May 19 (Xinhua) -- The U.S. Department of the Treasury's Office of Foreign Assets Control (OFAC) on Tuesday designated and blocked a prominent Iranian foreign currency exchange house and associated front companies, claiming they oversee hundreds of millions of dollars in transactions on behalf of sanctioned Iranian banks.

The action, part of the U.S. Economic Fury campaign, targets more than 50 companies, individuals and vessels generating revenue for Tehran, the department said in a press release.

In addition, OFAC also blocked 19 vessels involved in Iranian petroleum and petrochemical shipments to foreign customers, "transactions that have generated hundreds of millions of dollars in revenue."

The department is also prepared to take action against foreign companies supporting illicit Iranian commerce, including airlines, and may impose secondary sanctions on foreign financial institutions that facilitate Iran's activities, if necessary, the release said.