Media captionWhat is the Iran nuclear deal?
Much of the damage has already been done, with Trump's aggressive rhetoric fueling a run on the rial in recent months, while worsening inflation has stoked public protests against the government's management of the economy that have intensified over the past week.
A lot of the practical effects of the sanctions are yet to be seen, as they depend heavily on which nations go along with United States demands.
"The United States is fully committed to enforcing all of our sanctions, and we will work closely with nations conducting business with Iran to ensure complete compliance".
"We are always in favour of diplomacy and talks".
Rouhani said that Trump's call for direct negotiations with Iran were "only for domestic consumption in America. and to create chaos in Iran".
"Either change its threatening, destabilising behavior and reintegrate with the global economy, or continue down a path of economic isolation. I can't afford to buy food, pay the rent." said a construction worker on the streets of the capital.
"Consistent with President Trump's decision, the administration will be reimposing specified sanctions after August 6, the final day of the 90-day wind-down period", the White House said.
"The remaining parties to the JCPOA have committed to work on, inter alia, the preservation and maintenance of effective financial channels with Iran, and the continuation of Iran's export of oil and gas", the joint statement between the European Union and the E3 highlighted. "Negotiations with sanctions doesn't make sense".
Earlier this year, the central bank said it would unify the exchange rate at 42,000 rials to the dollar in an attempt to root out unregulated trading.
Responding to Mr. Trump's comments, Iran's President Hassan Rouhani said that Washington's call for new nuclear negotiations at the same time the US reimposes crippling sanctions "makes no sense".
The EU said it is simultaneously implementing a "blocking statute" as the new sanctions take effect, stopping European companies from complying with the USA sanctions unless they have permission to do so.
Trump's top security adviser on Monday urged Iran to take up an offer of talks with the United States or suffer more pain from economic sanctions, but Iran's president said Washington needed first to prove it can be trusted.
"We've seen company after company announce that they are getting out of Iran", the officials said.
US trade with Iran stood at $258 million (Dh948m) in 2016, according to the US Census Bureau, while exports to Iran from the European Union, which will be affected by secondary sanctions, were worth $13 billion past year.
Zarif suggested it was hard to imagine negotiating with Trump after he had torn up the 2015 nuclear deal, on which Iran and world powers had spent the "longest hours in negotiating history". "That is not going to happen".
There is a new confidence in Washington's foreign policy.