A senior Treasury official expressed skepticism that Iran would be able to find an alternative payment system to its Central Bank, which the United States has sanctioned in an effort to persuade Tehran to halt its quest for a nuclear weapons capability, Reuters reported.

"It's fair to say that we are going to be very skeptical about efforts to develop alternative payment methods," David Cohen, Treasury's undersecretary for terrorism and financial intelligence, said on May 10.

He added: "Our presumption going in is anyone buying oil from Iran is ultimately paying the central bank of Iran, even if there is some intermediary step."

Agence France Presse reported that Cohen also said the United States is urging Lebanese banks to take “extra” caution in handling financial transactions with Syria in order to prevent the regime from stashing money abroad.