Officials in Washington have warned that an interim accord on Iran's nuclear program does not open the door to new economic opportunities with Tehran.
"The New York Times" quotes Treasury Undersecretary David S. Cohen as saying that "Iran is not open for business," adding that "a vast network of complicated sanctions" remain in force.
He warned businesses not to engage in any deals past the deal's July 20 expiration.
The comments came as the U.S. Treasury Department announced a $152 million settlement with Luxembourg-based Clearstream Banking for having allowed Iran to bypass sanctions.
The Treasury Department said the action should serve as "a clear alert to firms operating in the securities industry that they need to be vigilant with respect to dealings with sanctioned parties."
The Obama administration has been facing increased criticism from supporters of strong sanctions against Tehran.
Based on reporting by "The New York Times" and AFP