The U.S. Treasury alerted global financial firms on Thursday to watch out for any attempts by Iran to evade economic sanctions as they get tougher.
"The practices involve the use of third-country exchange houses or trading companies that are acting as money transmitters to process funds transfers through the United States in support of business with Iran," that are not exempted or authorized, the Office of Foreign Assets Control said in an advisory.
Adam Szubin, the OFAC director, told reporters the trend is not limited to any one country.
But he said the tactic showed the steps Iran is taking to access foreign currency reserves after most of the large banks it dealt with in the past have been blacklisted by ongoing sanctions aimed at bringing it to the negotiating table over its disputed nuclear program.
Szubin said U.S. government was in the process of pursuing a number of cases to legally address the "evolving and emerging threat." He said to "stay tuned" for any specifics.
The scale of most of the transactions is in the "tens of thousands" of dollars while occasionally reaching the low hundreds of thousands, Szubin said. Mostly in dollars and euros, the transactions are aimed at shoring up Iran's rapidly declining foreign currency reserves, he said.
Since 2005, the Treasury Department has imposed more than $2 billion in fines on HSBC, Credit Suisse and Lloyds Bank for violating U.S. sanctions on Iran and other pariah governments.
In its advisory, the Treasury Department outlined certain scenarios for how financial firms might recognize Iranian abuse of exchange houses and trading companies in an effort to evade sanctions.
For instance, a specific entity may repeatedly attempt to send payments through the United States in apparent violation of U.S. sanctions, or the volume or frequency of payments involving an individual exchange house or trading company indicates an uncharacteristic spike in activity or is inconsistent with the type of business generally conducted.