As NPR's Colin Dwyer reported recently, "Since May, when President Trump vowed to unilaterally pull the US out of the Joint Comprehensive Plan of Action, his administration has telegraphed its intentions to restore the sanctions that had been lifted as part of the pact".
On Friday, the EU, Germany, Britain and France said in a joint statement that they "deeply regret the further reimposition of sanctions by the United States".
The macro reasons are that - unlike with the Obama administration sanctions that had basically unanimous global support - Russia, China and even the European Union, at least in principle, view the Trump US sanctions as a bad faith violation of the 2015 nuclear deal. However, he confirmed that eight countries had permission to keep buying Iranian oil for the time being, despite earlier threats of a tough line.
Mike Pompeo, the secretary of state, said the aim was to force Iran to "abandon its destructive activities".
The US side was unmoved. "Essentially the sanctions that were taken off are snapping back", said Katherine Bauer, the Blumenstein-Katz Family Fellow at the Washington Institute.
Iran's Foreign Ministry spokesman Bahram Ghasemi also predicted the sanctions will actually work against America's interests.
The sanctions cover Iran's banking and energy sectors and reinstate penalties for countries and companies in Europe, Asia and elsewhere that do not halt Iranian oil imports. Watch as we've already taken more crude oil off the market than any time in previous history.
Magic Johnson reprimands Walton after Lakers' 3-5 start
Walton, 38, owns a 64-108 record as an National Basketball Association head coach since being hired by the Lakers in 2016. He went on to say that as they have more time to play together as a team that they will turn things around on the court.
"Secretary Pompeo has been very clear that we have an ear open to what is possible. But they're not doing very well", he said, referring to the economic setbacks the country has already faced because of an earlier round of US sanctions.
'Our position remains that as long as Iran continues to meet the deal that exists, we will be committed to it too'.
Senior Iranian officials have dismissed concerns about the impact to its economy.
The countries will deposit Iran's revenue in an escrow account, US officials have said.
Iranian students stormed the US Embassy on November 6, 1979, shortly after the Islamic Revolution, taking 52 Americans hostage for 444 days.
He would not rule out the Trump administration extending the waivers beyond six months.
U.S. secretary of state Mike Pompeo has said the Trump administration is committed to reducing Iranian crude imports by its major buyers China and India to "zero" and warned ominously, but without specifics, "watch what we do".
Iran's supreme leader Ayatollah Ali Khamenei denounced the measures on Saturday, saying Trump had "disgraced" U.S. prestige and would be the ultimate loser in the long-running quarrel between the countries.