US President Donald Trump has claimed that talks with Iran are imminent and could happen “pretty soon,” a day after he expressed willingness to meet with the Islamic Republic's leaders without "preconditions."

"I have a feeling they'll be talking to us pretty soon," Trump said at a rally in Florida on Tuesday. "And maybe not, and that's OK, too."

The US president also used the occasion to once again denounce as "horrible, one-sided" the 2015 Iran nuclear deal – known as the Joint Comprehensive Plan of Action (JCPOA) – from which he withdrew in May.

Trump announced on Monday that he was willing to meet with Iranians “any time they want to.”

Shortly after that, US Secretary of State Mike Pompeo appeared on CNBC to set some conditions.

Iranian Foreign Ministry spokesman Bahram Qasemi responded to Trump's offer by noting that it was in contradiction his actions of imposing sanctions and pressuring other countries into avoiding business with Tehran.

"Sanctions and pressures are the exact opposite of dialogue which requires mutual respect and commitment to international treaties," he said. "How can he prove to the Iranian nation that the comments he made last night showed his true intention for negotiation and were not expressed for populist gains?"

Back in May, Pompeo had set 12 conditions for talks with Iran, which were dismissed by Tehran.

Trump’s latest stance towards Tehran runs counter to his recent threats against the nation as well as pulling Washington out of the Iran nuclear deal despite having the support of almost all US allies.

The withdrawal entails the re-imposition of not only sanctions on Iran but also the so-called secondary sanctions on third countries.

Iran’s President Hassan Rouhani has denounced the US withdrawal from the 2015 international nuclear deal, saying the ball is now in Europe’s court to make up for Washington’s absence and work to keep the landmark agreement alive.