The Trump administration has officially announced the reimposition of all US sanctions on Iran that had been lifted under the 2015 nuclear deal.
The sanctions cover Iran’s shipping, financial and energy sectors. They’re the second batch of penalties reimposed since President Donald Trump withdrew from the deal in May.
The White House said it would be the "toughest sanctions regime ever imposed on Iran".
The sanctions, which come into force Monday, penalise countries that don’t stop importing Iranian oil and foreign companies that do business with blacklisted Iranian entities.
Eight countries are getting waivers so they can continue temporarily importing Iranian oil.
Many EU countries who supported the nuclear deal said they would back companies doing legitimate business with Iran.
Secretary of State Mike Pompeo and Treasury Secretary Stephen Mnuchin made the announcement Friday.
They say sanctions will remain until Iran meets demands that include ending support for terrorism, ending military engagement in Syria and completely halting its nuclear and ballistic missile development.
Trump pulled out of the Iran Nuclear Deal in May, saying it was "defective at its core".
Iran says it is unconcerned by the move but analysts say the country is likely to be impacted.
Ali Vaez, Crisis Group's Project Director for Iran told Euronews: "I think it's very hard for [the Iranians] to deny the fact that their currency has lost two thirds of it's value and the Iranian oil exports are probably going to be cut by about 40 to 50 percent. So the impact on the Iranian economy, without any doubt, is going to be devastating."