President Donald Trump on Sunday said Iran would be bombed and face additional tariffs unless it agrees to a nuclear deal with the US.
"If they don't make a deal, there will be bombing. And it will be bombing the likes of which they have never seen before”, Mr Trump said in a telephone interview with NBC News. He added that no deal would also result in secondary tariffs "like I did four years ago."
Mr Trump's rhetoric intensified from his comment a few days earlier that if Tehran refused to negotiate a new nuclear agreement, "bad, bad things are going to happen to Iran." The specifics of whether Mr Trump was implying a unilateral US air strike or a joint operation with Israel remained unclear.
In his first term in office, Mr Trump withdrew the US from a 2015 deal between Iran and world powers that placed strict limits on Tehran's nuclear activities in exchange for sanctions relief. Mr Trump also reimposed sweeping US sanctions on the country.
Since then, Iran has far exceeded the uranium enrichment limits set out in the initial agreement. Tehran, deeply suspicious of the US administration after Mr Trump's withdrawal from the original nuclear deal, has so far rebuffed Mr Trump's warning to make a deal or face military consequences.
Iran last week issued a response through Oman to a letter from Mr Trump, in which he urged Tehran to reach a new nuclear deal, Iranian Foreign Minister Abbas Araghchi was quoted as saying by the official IRNA news agency.
Mr Araghchi said he believed it was no longer possible to revive the 2015 nuclear deal and that attempting to do so would not serve Iran's interests.
The Foreign Minister, who was among Iran's negotiators on the deal, said the agreement could not be revived in the same format because of advances in Tehran's nuclear development and increased US sanctions. However, Mr Araghchi suggested the deal could serve as a base for a potential agreement in the future.
In a video published early Sunday by Iranian state media, Iranian President Masoud Pezeshkian said that the country rejected direct nuclear negotiations with the US, but he left open the possibility of indirect talks.
It comes after weeks of seemingly mixed messages from within Iran. Videos from Quds Day demonstrations on Friday showed people instructing participants to shout only: “Death to Israel.” Typically, “Death to America” is also heard.
Video of an underground missile base unveiled by Iran's Islamic Revolutionary Guard Corps also showed its troops stepping on an Israeli flag painted on the ground. But there was no American flag, which is often also seen in such propaganda videos.
Western powers have accused Iran of aiming to develop nuclear weapons by continuing to enrich uranium to higher levels. Tehran says its nuclear programme is only for civilian purposes.