The sanctions, announced by the US departments of State and Treasury, apply to Iran’s Law Enforcement Forces and its commander Ismail Ahmadi Moghadam, and to Iran’s Islamic Revolutionary Guard Corps (IRGC) and the Basij Resistance Force.

The sanctions would freeze any of the targets’ assets under US jurisdiction and bar US persons and institutions from dealing with them. They also make Moghadam and potentially all members of the groups ineligible for US visas.

“Nearly two years after Iran’s brave citizens took to the streets, the struggle for civil liberties and fundamental rights continues,” said US Secretary of State Hillary Clinton referring to mass protests following Iranian President Mahmoud Ahmadinejad’s disputed re-election.

“Today, the United States has sanctioned three Iranian government entities complicit in the ongoing brutal repression,” she added.

The IRGC, which the Treasury blamed for violent crackdowns after the election, was already subject to the asset freeze and the ban on US dealings under October 2007 sanctions that target proliferaters of weapons of mass destruction.

As a result, the only new sanctions on the IRGC are the visa restrictions.

The practical effect of the steps may be limited because it is unclear to what extent, if at all, the groups have assets under US jurisdiction or their members may seek US visas.

A US official said that as a general rule, the government did not comment on the amount of assets frozen.

“We do not believe that the amount of assets frozen is an accurate indicator of the effect of our unilateral sanctions,” said the official, arguing that sanctions have a multiplier effect as non-US financial institutions cut off dealings with targeted groups to avoid falling afoul of US regulations.

“The voluntary implementation of US sanctions by nearly every major financial institution around the world amplifies the effect of US sanctions,” the official said.

“These designations highlight for the international community the IRGC’s continuing role in a broad range of illicit activities, which is an important part of our strategy to build and maintain a broad coalition of nations imposing sanctions against Iran,” the official added.

“The IRGC’s expanding influence and control over broader segments of the Iranian economy — and its continued involvement in a broad range of illicit activities, in this case, human rights abuses - has made is a primary focus of our efforts,” the official said.