The US is weighing case-by-case exemptions for some countries from the next set of sanctions - which take effect in 90 days - targeting Iranian oil exports, according to Trump administration officials who briefed reporters on Monday, despite its announced goal of allowing "zero" Iranian oil exports.
Iran is also taking solace in the fact that most of the world strongly opposes Trump's policy, with China, India and Turkey all saying they are unwilling to substantially cut purchases from Iran when the USA reimposes sanctions on the energy sector on November 5. "These are the most biting sanctions ever imposed, and in November they ratchet up to yet another level", Trump wrote in an early morning tweet Tuesday.
Iran is accusing the USA of reneging on the nuclear agreement, signed by the Obama administration, and of causing recent Iranian economic unrest.
The European Union's diplomatic chief, Federica Mogherini, said the union, as well as Britain, France and Germany, deeply regretted the U.S. move.
The ministers said the Iran deal is "crucial for the security of Europe, the region and the entire world", and the European Union issued a "blocking statute" Monday to protect European businesses from the impact of the sanctions. "That's the ask", said Pompeo on Sunday ahead of the re-imposition.
"It also forbids European Union persons from complying with those [US] sanctions unless exceptionally authorised to do so by the commission", said spokeswoman Mina Andreeva.
The EU has called on companies to increase their trade with Iran in defiance of Donald Trump's sanction on the country.
Whether to comply with United States sanctions or keep doing business in Iran is a "purely economic decision", one senior official argued.More news: Missing Iowa Jogger Mollie Tibbetts: Police Rule Out Possible Sighting
"The E.U.is morally bankrupt, and we need to remember that next time they try to lecture us", Mr. Erdan told Israel Radio.
Iran's president said the measures were "psychological warfare" which aimed to "sow division among Iranians".
European enterprises can either comply with United States sanctions and face consequences in Europe for violating the "blocking statute" or keep doing business in Iran and face USA sanctions.
"If you stab someone with a knife and then you say you want talks, then the first thing you have to do is remove the knife", Rouhani said in a speech broadcast live on state television.
Iran's central bank, acting on the eve of the U.S. move, scrapped most currency controls introduced this year in a bid to halt a plunge in the rial that has stirred protests against the government.
He said Washington was becoming isolated internationally and would come to regret imposing sanctions against the views of its allies and other world powers. "But if the government has a serious plan they can control the situation".
The new United States sanctions will likely slash oil supply.
But many large European firms are leaving Iran for fear of U.S. penalties, and Trump warned of "severe consequences" for firms and individuals that continued to do business with Iran.