Reuters ^[1]
Dec 7, 2012

The United States has aggressively ramped up its use of financial sanctions this year to pressure Iran to stop pursuing nuclear weapons, but a measure that takes effect in February could have the most dramatic impact yet, the Treasury Department’s top sanctions official said on Thursday.

Starting Feb. 6, US law will prevent Iran from repatriating earnings it gets from its shrinking oil export trade, a powerful sanction that will “lock up” a substantial amount of Tehran’s funds, said David Cohen, undersecretary for terrorism and financial intelligence at the US Treasury Department.

“Iran’s oil revenues will largely be shackled within a given country and only useable to purchase goods from that country,” Cohen said in a speech to the Foundation for Defense of Democracies, a group that has advocated for tougher sanctions.

A year ago, the US Congress passed a law requiring buyers of Iranian oil to make significant cuts to their oil purchases, or risk being cut off from the US financial system.

Full article here ^[1]