The sanctions are meant to impose restrictions on funding for the IRGC's "malign activity".
Mnuchin: Iran funds the world's largest stated sponsored terror
"Countries around the world must be vigilant against Iran's efforts to exploit their financial institutions to exchange currency and fund nefarious actions of the IRGC-QF and the world's largest state sponsor of terror," US Treasury Secretary Steve Mnuchin, said.
Iran's central bank expected to be on sanction list soon
Although Iran's central bank wasn't sanctioned in this round, it's expected to be added to the list as the US seeks to cut Iran off from dollars.
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A background on the IRGC
The Islamic Revolutionary Guard Corps (IRGC) was set up immediately after Iran became an Islamic republic in 1979, after clerics seized power from the monarchy under the leadership of Ayatollah Khomeini. In October 2017, Trump called the IRGC a "corrupt terror force and militia".
The Trump administration is flexing its economic muscles
After pulling out from the nuclear deal, the Trump administration is leveraging the US' economic power and the power of the US dollar as the world's reserve currency to pressurize Iran.
The Trump administration wants a new nuclear deal permanently restricting Iran's nuclear programme and ballistic missile programme, and wants Tehran to withdraw support to militants in the region.
The US is planning to rally allies to pressurize Tehran
In a bid to press its case, the US is now planning to send officials to several nations in Asia, Europe, and the Middle East.
The aim of the activity would be convince as many countries as possible to impose sanctions on Iran.
The idea, however, is not to ruin Iran's economy, but to pressurize Tehran into negotiating new terms.