Iran's response comes a day after a senior US administration official said Donald Trump is expected to announce soon that he will decertify the deal, in a step that could cause the accord to unravel.
Iranian President Hassan Rouhani defended the nuclear deal with Western powers on Saturday and said that US President Donald Trump could not undermine it.
Under the 2015 deal, Iran agrees to limit its disputed nuclear programme in return for the easing of economic sanctions.
However, Trump is expected to announce soon that he will decertify the deal, a senior administration official has said, in a step that potentially could cause the accord to unravel.
"In the nuclear negotiations and agreement we reached, issues and benefits that are not reversible. No one can turn that back, not Mr. Trump or anyone else," Rouhani said at a ceremony at Tehran University, according to state media.
"Even if 10 other Trumps are created in the world, these are not reversible."
Rouhani said if the US violated the deal then it would hurt its own reputation in the international community.
"If America carries out any violations today, the whole world will condemn America. They will not condemn Iran," Rouhani said.
Trump, who has called the pact an "embarrassment" and "the worst deal ever negotiated", has been weighing whether the deal serves US security interests as he faces the October 15 deadline for certifying that Iran is complying with its terms.
This is despite the fact that UN inspectors have verified Iranian compliance with the terms.
The prospect of Washington reneging on the deal has worried some of the US allies that helped negotiate it, especially as the world grapples with another nuclear crisis, North Korea's nuclear and ballistic missile development.
If Trump does not certify that Iran is in compliance, the US Congress will have 60 days to decide whether to reimpose sanctions waived under the deal.
Russia: 'deal should be preserved'
Russian Foreign Minister Sergei Lavrov said on Friday he hoped US Trump would make a "balanced" decision on whether to remain engaged in the landmark international deal to curb Iran's nuclear programme.
"It is very important to preserve it in its current form and of course the participation of the United States will be a very significant factor in this regard," Lavrov told reporters on a visit to Kazakhstan.
EU Commission reacts
The European Commission said on Friday that an international deal to curb Iran's nuclear programme struck in 2015 was working and all sides should stick to their commitments.
"We are following very closely all the developments on the deal... reminding that it is a non-proliferation deal, which has been endorsed by the UN Security Council, that it's working, delivering as it has been verified eight times by the international agency for atomic energy," a Commission spokeswoman told a news conference in Brussels.
"It is a durable, long-term solution to the Iranian nuclear issue which gives all sides the necessary assurances and we expect all sides to stick to their commitments under the deal," she added.
'Calm before the storm'
The president on Thursday had tough words for Iran, saying the country had not lived up to the spirit of an agreement forged with world powers to curb its nuclear program.
A senior administration official said on Thursday that Trump was expected to announce soon he would decertify the landmark agreement. Trump's deadline is October 15.
After discussing Iran and North Korea with US military leaders on Thursday Trump posed for a photo before dinner and declared the moment to be "the calm before the storm."
The White House did not immediately reply to a request to clarify Trump's remark.