President Hassan Rouhani said on Sunday Iran had prepared plans to respond to any decision by US President Donald Trump to end the nuclear agreement with Tehran and that the US would regret such a decision.
"We have plans to resist any decision by Trump on the nuclear accord," Rouhani said in a speech carried live by state television.
"If America leaves the nuclear accord, this will entail historic remorse for it."
The statement comes just days before Trump will have to make a dramatic decision on the fate of the nuclear deal with Iran.
Trump is "committed" to regime change in Iran, Trump's lawyer and confidant Rudy Giuliani said on Saturday.
Giuliani, the former New York City mayor, said at an event hosted by an Iranian opposition group in Washington that regime change in Iran is "the only way to achieve peace in the Middle East," according to a Haaretz report.
Giuliani believes Trump will withdraw the United States from the 2015 deal with Iran.
"With Secretary of State Mike Pompeo on his right side, and National Security Adviser John Bolton on his left side, what do you think is going to happen to that agreement?" Giuliani asked.