The agreement was a “done deal” and there would be no attempts to sabotage it, said Alireza Zakani, a senior figure in the hardliners’ camp and a former MP.
“We consider the nuclear accord a done deal and will remain committed to it unless the US officially withdraws from it,” Mr Zakani, who led opposition to the nuclear deal in parliament, told the Financial Times.
The accord, which US President Donald Trump has repeatedly threatened to unravel, has become a critical battleground between hardliners and reformists ahead of the May 19 presidential vote.
It was the signature achievement of Mr Rouhani, the centrist president who signed the deal in 2015 and who is seeking a second term. His supporters say the agreement, which brought the lifting of many sanctions, has enabled Iran to double oil production, boost a struggling economy and reach out to foreign investors.
Mr Rouhani has repeatedly said the deal “has deterred the shadow of war from the country”.
But reformists have been worried that hardliners will seek to make political capital out of escalating tensions with the US to portray Mr Rouhani as weak and naive.
Mr Trump has warned that Iran is “on notice” and has taken a far more belligerent stance towards Iran than Barack Obama, his predecessor. As well as criticising the nuclear deal, Washington has condemned Iran’s missile programme and its role in regional conflicts, including Syria.
Hardliners say the nuclear accord has failed to deliver benefits to Iranians and rail against the notion of engagement with the west, particularly the US. They note that the US sanctions related to Iran’s alleged sponsoring of terrorism remain in place, making western banks wary of doing business related to Iran.
“Mr Rouhani! How quickly you shook hands with the enemy [the US]?” an organiser of a campaign rally for Ebrahim Raisi, one of the hardliners’ main candidates, told his supporters this weekend. “Rouhani’s government is a government of humiliation.”
The crowd shouted: “We don’t want a US-backed government.”
Mr Raisi, a senior cleric and former prosecutor-general, also said it was wrong to “seek help from the outside” to solve the country’s economic problems.
“Why have you [Mr Rouhani] kept the country idle for four years, waiting for others to open the knots?” he said. Thousands of his supporters responded by chanting “death to the US”.
Mohammad Baqer Qalibaf, the powerful mayor of Tehran and the other top hardline candidate, said on Monday that he would safeguard the nuclear accord because it had been backed by the Islamic establishment. But he also used it to criticise Mr Rouhani’s record.
“The people’s question today is how they have benefited from this agreement? This is a serious weakness of the current government,” he told local television.
Mr Zakani, who registered as a candidate but did not clear the constitutional watchdog that approves contenders, said criticism of the deal was fuelled by the belief that Iran could have got better terms.
Under the accord, signed by the US, China, Russia, the UK, France and Germany, Iran agreed to cut back its nuclear activities.
“We will diligently pursue our rights under the deal in the face of violations of the agreement by the US which continues its threats against Iran and obstructs the lifting of [all] sanctions,” Mr Zakani said.
But hardliners seem to have no intention to provoke Mr Trump if they succeed in unseating Mr Rouhani
“Trump is . . . behaving like a predatory animal and an unpredictable figure to scare others. [But] his teeth and claws will not intimidate us,” Mr Zakani said. “We should not respond to everything a mad person says.”