The White House today announced new sanctions on Iran — specifically on the volunteer Basij militia, which operates under the auspices of the Islamic Revolutionary Guard Corps (IRGC). The sanctions also target three Iranian banks accused of providing financial support to Basij-controlled companies.

The paramilitary force is tasked with exerting the IRGC’s will over Iranian society. But it also fights on behalf of the Bashar al-Assad government in Syria.

Why it matters: The announcement comes as the Donald Trump administration hopes to dissuade other countries from doing business with Iran following the US withdrawal from the nuclear deal. Washington is set to reimpose major sanctions on Iran’s energy sector next month.

“This is the quintessential example of why we still often talk about the dangers of doing business in a country that has widespread malign activity,” a senior administration official said on a background call with reporters. “There is so much obfuscation in Iran and no transparency, which makes it extremely difficult to know what you’re dealing with and what your business activities are actually funding.”