US President Donald Trump reiterated on Wednesday that Iran “will never have a nuclear weapon," while lauding the US military’s operations in Iran.

Speaking at a rally at the National Mall in Washington, DC, Trump said, “Last week we signed a historic agreement to end the conflict with Iran, fully open the Strait of Hormuz and accomplish what no president has ever been able to accomplish before: Iran will never have a nuclear weapon, that's done."

“And thanks to the power and skill of the United States Armed Forces," he continued, “today Iran has no Navy, no Air Force, no anti-aircraft capacity, no missile launchers, no manufacturing, and their leadership has been obliterated."

The President expressed confidence that regional peace is coming, saying, “And for the first time in 3,000 years, we are finally going to have peace in the Middle East. We're going to have peace in the Middle East."

He noted the decline in oil prices: “Today it hit a new low, and the world is a much safer place. We had to make that little journey to Iran to do what we did. Very soon you'll be at $2.50 a gallon for gasoline, and even lower than that, just like it was before we took the nuclear weapon away from Iran."

Trump’s comments came a day after he warned that the United States could quickly resume military action against Iran, should the Islamic Republic fail to act “reasonably" following the recent agreement.

"Iran has been great - IF Iran is reasonable, IF they're smart. Otherwise, we'll have to finish the job," Trump said at a rally in Pennsylvania.

He added, "As you know, we just achieved a historic peace agreement with Iran to end the conflict... and most importantly, we are ensuring one thing very importantly- because this is why I did it... Iran will NEVER have a nuclear weapon, and they've agreed to that."

Earlier on Wednesday, Secretary of State Marco Rubio stressed that Iran must fulfill commitments made during talks in Switzerland.

“We expect them to live up to the commitments they made in Switzerland," he told reporters. “If they don't live up to those commitments, the President has a lot of options at his disposal, including, I'm not saying he's going to do it, I'm saying including reversing these sanctions."

He added, “They've made very straight-up commitments in Switzerland, and the President has been very clear they need to keep those commitments."

Rubio also emphasized that any future agreement with Iran must be fully implemented.

“If we're going to get a deal, it has to be a real deal, and it has to be a good deal," he said. “If Iran wants to make a good and real deal, the United States is open to that. If they're not, then, of course, the President has options."