Iran's supreme leader Ayatollah Ali Khamenei condemned the new sanctions and promised a stronger response.
Rouhani sworn in as US slaps new sanctions on Iran
Iranian president Hassan Rouhani began his second term on Thursday as the nuclear deal with world powers that helped him win re-election came under increasing pressure from both Iran and Washington.
New US sanctions imposed a day before Mr Rouhani's swearing-in were immediately condemned described by Iran as a violation of the 2015 accord — known as the Joint Comprehensive Plan of Action (JCPAO) — with supreme leader Ayatollah Ali Khamenei promising a stronger "response to the hostility".
Mr Rouhani had promised Iranians he would use the deal to re-integrate Iran with the global economy and boost the economic prospects of Iranians. But thanks to resistance from Washington and vested interest among Iran's hardliners, the country's burgeoning young population has seen little discernible change.
And despite his re-election and promise to "insist on constructive engagement with the world more than before," Mr Rouhani faces scepticism both from Washington and Iran’s unelected establishment.
Mr Khameini said the new sanctions — imposed over Iran’s ballistic missile programme, which is not covered by the JCPAO — showed American would “use any excuse to make a fuss” He added, “You launch a satellite-carrying missile, they make noise. The response to the hostility is to become stronger.”
Abbas Araghchi, a lead Iranian negotiator on the nuclear deal, also said the new US sanctions violated the agreement.
In its latest test of missile technology, Iran last month launched a new rocket capable of carrying a satellite into space, but one that also uses technology needed for a nuclear-capable intercontinental ballistic missile. Such tests would only be a violation of the nuclear accord if they were specifically designed for the delivery of atomic weapons.
The test drew a rare joint condemnation from France, Britain and Germany, who have so far sought to protect the nuclear accord and have urged Mr Trump to abide by it.
Even before taking office Mr Trump had vowed to kill what he called "the worst deal ever " and has certified Iran's adherence to it every 90 days only grudgingly. Despite all advice to the contrary, Mr Trump has also made it clear that he is looking for ways to either scrap the deal or declare Iran to be in violation of it. According to The New York Times, US officials have already warned European counterparts to prepare to renegotiate or the US would pull out unilaterally just as it did from the Paris climate accord.
Since the last certification two weeks ago, Mr Trump has told the Wall Street Journal that if it were up to him, he “would have had them non-compliant 180 days ago” and that he “personally” expects to declare Iran in violation ahead of the next certification deadline.
One option the administration is considering is forcing inspections of Iranian military sites where illegal nuclear enrichment could take place. But a majority of the signatories of the deal would have to agree, and there is no evidence Iran is carrying out weapons-grade enrichment. Even with European support — which is unlikely — if Iran refuses to allow inspectors in, the US could use that to justify scuttling the deal. The other signatories would blame Washington, not Tehran, they would be highly unlikely to reapply international sanctions, Iran could then resume enrichment unimpeded and the path to possible military confrontation would be set.
“It could force the Iranian leadership to believe that nuclear weapons are essential for their survival,” Amir Handjani, a fellow at the Atlantic Council, wrote on Wednesday. “This is precisely the situation that the United States faces presently with North Korea, which virtually holds East Asia hostage because of its nuclear arsenal.”
France, Germany and Britain have joined the US in complaining about Iran's latest launch, calling it "threatening and provocative" in a joint letter to the UN secretary-general on Wednesday. .
European aircraft and energy companies have signed large deals with Iran, and are broadly supportive of Mr Rouhani.
"What Iranians are banking on at the moment, maybe overestimating, is that Europe will safeguard and build on the deal, and make it too politically costly for Trump to tear it up, or at least show Washington that if it walks away, it will be doing so alone," said Ellie Geranmayeh of the European Council on Foreign Relations.
It is also unclear how far America's regional partners, Saudi Arabia and the UAE, would back a complete US pullout, especially when the Gulf is already in turmoil.
As Hussein Ibish of the Arab gulf States Institute in Washington pointed out, "Whatever their reservations about the nuclear agreement, Gulf Arab countries understand that the ideal scenario for Iranian hardliners would be for the JCPOA to collapse in the near future."