US President Donald Trump declared that only the complete dismantling of Iran’s nuclear program would be acceptable to him, warning of catastrophic consequences should Tehran acquire a nuclear weapon.

Speaking in a televised interview on NBC's "Meet the Press," Trump clarified, “Total dismantlement. Yes, that is all I would accept.”

He added, “I want Iran to be really successful, really great, really fantastic. The only thing they can’t have is a nuclear weapon.”

Trump emphasized that Iran must renounce any ambitions of developing such arms, stating “the world will be destroyed” if the Islamic Republic succeeds in developing them.

The comments were made as diplomatic efforts between the United States and Iran suffered another setback. A planned fourth round of negotiations, which was to take place in Rome over the weekend, was postponed without a new date announced.

The postponement came despite the fact that last week, after the third round of talks between the US and Iran, a US official told Axios that the talks “were positive and productive. There is still much to do, but further progress was made on getting to a deal."

Trump has repeatedly said he prefers to solve the nuclear standoff with Iran through a deal, but has also not ruled out military action against Iran.

Several weeks ago, the US President said that, if military action is required to thwart Iran’s nuclear program, Israel will be involved and even lead the effort.

“With Iran, if it requires military, we’re going to have military. Israel will be the leader of that. But nobody leads us, we do what we want to do,” Trump told reporters at the Oval Office.

Asked what his deadline would be for Iran to reach a deal, the President replied, “I can’t really be specific, but when you start talks, you know if they’re going along well or not, and I would say the conclusion would be when I think they’re not going along well."

Last week, Trump expressed optimism that a deal could be reached between the US and Iran on the Islamic Republic’s nuclear program.

"On the Iran situation, I think we're doing very well. I think a deal is going to be made there. That's going to happen. Pretty soon it's going to happen,” Trump told reporters.

“We'll have something without having to start dropping bombs all over the place," he added.