An official, who spoke on condition of anonymity, told Reuters that the military site that was struck was an Iranian ground control station in Iran's Bandar Abbas that was about to launch a fifth drone.

The crucial port city of Bandar Abbas occupies a a strategic position on the Strait of Hormuz and has been a target of attacks since the war began on February 28. 

Iran has 440.9 kilograms (972 pounds) of uranium that is enriched up to 60 per cent purity, a short, technical step from weapons-grade levels of 90 per cent, according to the International Atomic Energy Agency. Iran has not publicly committed to giving up its uranium.

According to two regional officials and one senior Trump administration official, Iran would agree to give up its stockpile of highly enriched uranium - a key Trump demand - in return for sanctions relief under a potential deal.

One regional official, with direct knowledge of the negotiations, said how Iran would give up the uranium would be subject to further talks during a 60-day period. Some would likely be diluted, while the rest would be transferred to a third country, the official said.

Trump said that he "wouldn't be comfortable" with either Russia or China taking Iran's stockpile of highly enriched uranium.

Thursday's strikes are the second in the last four days. On Monday, US forces carried out what the Pentagon called "defensive" strikes on missile launch sites and minelaying boats in southern Iran.

The US said it acted with "restraint" in light of the weeks-long ceasefire, while Iran decried the action as a sign of "bad faith and unreliability."

The attack comes a day after US President Donald Trump asserted that Iran is "negotiating on fumes" and insisted that November's midterm elections won't make him rush into a deal to end the nearly three-month-old conflict that's spurred unease across the global economy.

Over the weekend, he even declared that his administration and Tehran had "largely negotiated" a settlement, though the talks are still in flux.

The President is looking for a settlement that will reopen the Strait of Hormuz and provide him with a credible argument that Iran's nuclear capability has been diminished enough to declare victory, winding down a conflict that's been politically unpopular for Republicans.

"They want very much to make a deal," Trump said. "So far, they haven't gotten there. We're not satisfied with it, but we will be — either that or we'll have to just finish the job."

The US military carried out new strikes overnight in Iran targeting a military site that officials believed posed a threat to US forces and commercial maritime traffic in the Strait of Hormuz.

An official told Reuters that the US military has also intercepted and shot down multiple Iranian drones that posed a similar threat.