() President Donald Trump is aggressively pushing Iran to sign a deal that would restrain its nuclear program, but his pullout from the original deal could make it more difficult for the nations to come together for a new agreement. 

Iran said it would retaliate against the U.S. with a “strong blow” if attacked over its refusal to agree. 

The threat comes days after Trump warned Iran he would bomb in a manner “never seen before” should it not sign off on a nuclear weapons deal. 

Trump sent a letter to Iran’s supreme leader, Ali Khamenei, earlier this month, seeking a new deal to replace the agreement he withdrew from in 2018.

Iran said Sunday it rejected direct negotiations with the U.S. but said it was open to indirect talks. 

Trump withdrew the United States from the deal during his first term, claiming it was “one of the worst and most one-sided transactions the United States has ever entered into.” 

The US signed a nuclear deal with Iran in 2015 

The Iran nuclear agreement was called the Joint Comprehensive Plan of Action (JCPOA) and was signed in 2015 by Iran and several nations, including the United States under the Obama administration.

Under the deal, Iran agreed to dismantle much of its nuclear program and open its facilities to more international inspections in exchange for the lifting of economic sanctions. 

The signatory nations had intended to curtail Iran’s nuclear program to the point that if the nation decided to pursue a nuclear weapon, it would take at least one year, giving world powers time to respond, according to the Council on Foreign Relations. 

At the time, U.S. intelligence officials estimated that, in the absence of an agreement, Iran could produce enough nuclear material for a weapon in a few months. 

Iran had complied with the agreement, pulling back its proliferation by 2016. In return, the United States, European Union, and United Nations held up their end of the bargain by repealing or suspending their sanctions. 

The U.S. and other nations also unfroze about $100 billion worth of frozen Iranian assets, according to the Council on Foreign Relations. 

The Obama administration also cut secondary sanctions on the oil, which allowed Iran to significantly increase its oil exports. 

Trump pulls out of the original nuclear deal in his first term 

The deal came to a crashing halt after Trump unilaterally withdrew the United States from the nuclear agreement and reimposed sanctions lifted under the agreement in 2018 during his first term. 

At the time, he said it didn’t do enough to stop the nation from nuclear development. 

“We cannot prevent an Iranian bomb under the decaying and rotten structure of the current agreement,” the president said at the time about his decision. 

His first administration stated that the deal “enriched the Iranian regime and enabled its malign behavior, while at best delaying its ability to pursue nuclear weapons and allowing it to preserve nuclear research and development.” 

Trump also said that the deadlines under the deal were faulty and would enable Iran to pursue nuclear weapons in the future.

The move was seen by many as a rebuke of his predecessor Obama and a firmer alliance to Israel, which had long opposed the deal. 

Iran views Trump’s pullout as one-sided

Trump’s pullout severely damaged trust between the nations, and although the remaining signatory nations tried to salvage the agreement, Iran backed away from the terms.

Iran abandoned all limits that the deal put on its program and enriched uranium to up to 60% purity near weapons-grade levels of 90%.

Surveillance cameras installed by the International Atomic Energy Agency, the United Nations’ nuclear watchdog, have been disrupted while Iran has barred some of the Vienna-based agency’s most experienced inspectors. Iranian officials also have increasingly threatened that they could pursue atomic weapons.

Is a new Iran nuclear deal possible?

While Iran has hinted at an openness to potentially negotiate another nuclear deal, challenges are ongoing. 

Since Trump returned to the White House, his administration has consistently said that Iran must be prevented from acquiring nuclear weapons. 

Trump has warned that an imposition of “secondary tariffs” on Iranian oil would be possible should the country not agree to a deal, meaning that countries that buy Iranian oil would be faced with U.S. tariffs.

Iran President Masoud Pezeshkian says the country has no plans to directly negotiate with the U.S., writing, “We don’t avoid talks; it’s the breach of promises that has caused issues for us so far. They must prove that they can build trust.” 

The Associated Press contributed to this story.