The 2015 deal, one of former President Barack Obama's biggest diplomatic achievements, gave Iran billions of dollars in sanctions relief in exchange for curbs on its nuclear program, which many believed it was using to develop atomic weapons.
Iranians suffered a great deal under the sanctions that were lifted by the nuclear deal in July 2015; they are not ready for a new round of sanctions that Trump has promised will be tougher and more painful than before.
The late founder of the Islamic Republic, Imam Khomeini, hailed the takeover as a "second revolution" after the 1979 Islamic Revolution toppled the Shah of Iran, who was a close ally of the USA in Iran. Some said they're already used to them, while others chose to downplay the effect.
Saying it is "outrageous" for the Trump-Pence "administration to feign concern for the Iranian people while imposing sanctions", Paul Kawika Martin, senior director for policy and political affairs at Peace Action, said the move "should be seen for what it is: the latest step in a calculated campaign by this White House to provoke war with Iran".
Since that time, the USA president and key officials within his administration have repeatedly voiced their opposition to negotiating with Tehran, a position that pits Washington against several of its key European allies, which remain committed to the 2015 agreement. However, firms in these countries have backtracked on early agreements to develop Iran because the U.S. has threatened to impose sanctions on firms trading with the Islamic state.
Washington will reapply far-reaching sanctions on Iran's petroleum and banking sectors starting on Monday.
Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei said on Saturday the United States has been trying for the past 40 years to regain the domination it had over Iran under the Shah but to no avail.
Iraq is among eight Iranian oil importers expected to receive waivers to bypass the upcoming sanctions.
"India said to the United States that they can´t stop before March, they are facing a major currency crisis", explained Joel Hancock, analyst at Natixis. They pledged to protect European companies from the sanctions. Those that buy oil from Iran after the cutoff could be penalized, through fines or exclusion from the U.S. financial system.
Eight countries, though, are receiving waivers that will allow them to keep buying oil from Iran without coming under US sanctions: Pompeo did not identify the countries, but Bloomberg reported that four are Japan, India, China and South Korea.
The regime in Tehran has been doing its best in the past few months to find a way to avoid these sanctions, mainly by working with the European Union, but it is still struggling to persuade its citizens that any such mechanism will work.
India kept importing oil from Iran knowing it well that it will be saved from sanctions on being strategic partner of the US.
Countries with close security and trade ties with the United States were quick to cut their purchases - South Korea went nearly straight to zero, with Japan and much of Europe close behind.