Iran has rejected an offer from former U.S. President Donald Trump to engage in direct negotiations over its nuclear program, opting instead to keep the door open to indirect discussions through intermediaries, Iranian President Masoud Pezeshkian said on Sunday.

"We responded to the US president's letter via Oman and rejected the option of direct talks, but we are open to indirect negotiations," Pezeshkian stated during a cabinet meeting, according to reporting by Iran's ISNA news agency.

The announcement followed reports that Trump had recently sent a letter to Iran's Supreme Leader Ayatollah Ali Khamenei urging negotiations and warning of consequences if Tehran refused. "I would rather negotiate a deal. I'm not sure that everybody agrees with me, but we can make a deal that would be just as good as if you won militarily," Trump said in an interview with Fox Business News. "But the time is happening now. The time is coming up. Something's going to happen one way or the other."

While Pezeshkian did not detail the contents of Trump's letter, he confirmed it was transmitted through Oman. Iran's leadership has continued to reject direct dialogue with Washington, particularly under Trump, who unilaterally withdrew the U.S. from the 2015 nuclear accord in 2018 and reimposed sanctions that have since crippled Iran's economy.

In an interview taped before Pezeshkian's comments, Trump told NBC News: "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." He added, "There's a chance that if they don't make a deal, that I will do secondary tariffs on them like I did four years ago."

Kamal Kharrazi, a senior adviser to Ayatollah Khamenei, said Iran had not ruled out negotiations entirely. "It is ready for indirect negotiations with the United States in order to evaluate the other party, state its own conditions and make the appropriate decision," Kharrazi said, according to Iranian state media.

Tensions between the two countries remain high as the International Atomic Energy Agency (IAEA) reported last month that Iran had "significantly increased production and accumulation of high enriched uranium." While Tehran maintains its nuclear program is intended for peaceful purposes, U.S. and Israeli officials have expressed alarm over uranium enrichment nearing weapons-grade levels.

Barbara Slavin, a fellow at the Stimson Center in Washington, told Al Jazeera: "The Iranians are, right to be distrustful, given Trump's track record and withdrawing from a previous deal." She added, "The Iranians are worried, but mostly about the economic impact of Trump's sanctions, the resumption and increase in economic sanctions, which we've already seen. The Iranian currency has depreciated dramatically. There's high inflation and unemployment, and I think this frankly worries the Iranians more than a physical attack, which if anything, might unify the country."

Slavin also noted the U.S. military buildup in the region. "The US has moved additional bombers to Diego Garcia. It's got another aircraft carrier apparently coming into the region. So it is well positioned to carry out some sort of military action, possibly in conjunction with the Israelis if there isn't movement toward a diplomatic settlement," she said.

Khamenei has remained adamant in public statements that Tehran will not bow to U.S. pressure. "If they do anything malign to the Iranian nation, they will get a hard slap," Khamenei said last week, according to Iranian state media. He also warned that U.S. threats "will get them nowhere."