President Donald Trump said he sent a letter to Iran’s supreme leader this week expressing interest in negotiating a nuclear deal amid growing concerns the Islamic Republic could develop nuclear capabilities in the near future.

“I said I hope you’re going to negotiate, because it’s going to be a lot better for Iran,” Trump said in an interview with Fox Business Network that aired on Friday. “I think they want to get that letter. The other alternative is we have to do something, because you can’t let them have a nuclear weapon.”

Trump claimed he sent the letter on Wednesday, though Iran’s mission to the United Nations said that the country had not yet received the message, according to Reuters.

“There are two ways Iran can be handled: militarily, or you make a deal,” Trump said of his approach to the regime. “I would prefer to make a deal, because I’m not looking to hurt Iran. They’re great people.”

“I’m not sure that everybody agrees with me,” he added.

Last month, Trump pledged to negotiate what he called a “verified nuclear peace agreement” with Iran, hours after his administration moved to reimpose its maximum pressure campaign against the Islamic Republic, including harsh sanctions on oil exports.

Trump has sent mixed signals about his approach to Iran. In his first term, he withdrew from the nuclear deal brokered by the Obama administration in 2015 — dismissing it as a “horrible, one-sided” agreement “that should have never, ever been made.”

But he has more recently demonstrated interest in renewing discussions with Iran as he continues to upend U.S. foreign policy while engaging directly with Hamas and pursuing diplomacy with Russia, which has offered to help mediate negotiations with Iran.

The pro-Israel lobbying group AIPAC, which fiercely opposed the Obama administration’s efforts to broker a deal with Iran, said that it was receptive to Trump’s desire to renew outreach to the Islamic Republic.

“We strongly support the Trump administration’s demand that Iran verifiably give up its nuclear weapons program,” Marshall Wittmann, an AIPAC spokesperson, told Jewish Insider. “The president’s swift implementation of maximum economic pressure, coupled with the threat of military action and support for our ally Israel, is essential to create the conditions for timebound negotiations to try to achieve a deal that permanently and verifiably prevents Iran from acquiring nuclear weapons.”

Wittmann urged “Democrats and Republicans in Congress to work with the administration to further enforce sanctions, strengthen our ally Israel, and reaffirm that preventing Iran from acquiring a nuclear weapon is a national security priority.”

Behnam Ben Taleblu, a senior fellow at the Foundation for Defense of Democracies think tank who specializes in Iran, said Trump’s letter “shows that the president really is considering all options, and is yet another indicator of his seriousness for a diplomatic resolution.”

But, he warned, “it takes two to tango,” noting that Iran “has not amassed all this atomic infrastructure and know-how to merely trade it away at the right time.”

“Rather than take to letter writing and emulating the failed outreach of his predecessors,” Ben Taleblu told JI, “Trump would be wise to marry his own successful policy to maximum pressure against the regime in Iran with maximum support for the people in Iran to box in and challenge the very same regime which has tried to kill him.”

Michael Makovsky, president and CEO of the Jewish Institute for National Security of America, also advised caution on pursuing negotiations. Even as he praised Trump’s “strong support for Israel and tough posture on Iran,” Makovsky said it is “dangerous to U.S. interests to enter talks with Iran at this late stage, and the U.S. could be walking into quicksand.”

“As recent decades prove, Iran will try to drag out talks while they advance their nuclear program, which has already reached a very dangerous and critical level,” Makovsky told JI, adding that JINSA had recently recommended a range of steps Trump should take if he moves forward with negotiations.

Trump “needs to state the goal of” such nuclear talks “is an agreement, requiring Senate ratification, to completely, permanently and transparently dismantle Iran’s nuclear program,” Makovsky said.

In comments on Friday, Trump reiterated his hope to negotiate a renewed nuclear agreement with Iran. 

“There will be some interesting days ahead with Iran,” he said. “We are down to final strokes with Iran. We are down to the final moments. We can’t let them have a nuclear weapon. Something is going to happen very soon. I would rather have a peace deal than the other option, but the other option will solve the problem.”