It was Washington's fourth round of sanctions on Iran's oil sales since President Donald Trump said in February he was re-imposing a "maximum pressure" campaign.
These actions followed multiple executive orders targeting Iranian oil sector sales, following a presidential memorandum to put maximum pressure on Iran.
The sanctions were being done to "stem the flow of revenue the regime uses to fund destabilizing activities."
Tehran is wary of Trump's new sanctions, and it risks seeing its economy be battered - but does not want to be seen to buckle.
The US Treasury said that both countries targeted the US 2024 presidential election and 'sought to divide the American people through targeted disinformation campaigns.'
The rial’s stronger value in 2015 during Iran’s nuclear deal, when it traded at 32,000 to the dollar, contrasts sharply with today’s conditions.
The European Union also agreed to impose sanctions on seven people and seven organizations, including airline Iran Air, for their links to Iranian transfers of ballistic missiles to Russia.
The US, following the implementation of sanctions, said that the action targets Iran's vast shadow banking system used to support Iran's military.
Washington also targeted two companies and a vessel involved in the shipment of Iranian commodities.
Iran launched more than 300 drones and missiles on Israel in what it said was retaliation against a suspected Israeli bombing of its embassy compound in Damascus.