The US Central Command made the announcement in a post on social media site X.
"US forces struck Iranian military command centres, maritime capabilities, missile and drone launch sites, and air defence systems to degrade Iran's ability to continue attacking commercial vessels flowing through the Strait of Hormuz," CENTCOM said.
The latest round of strikes on Iran lasted about five hours, according to the US military.
Washington said it is attempting to "degrade Iran's ability to continue attacking commercial vessels flowing through the Strait of Hormuz."
Meanwhile, a tanker was struck by an unidentified projectile in the Strait of Hormuz off the coast of Oman, the United Kingdom Maritime Trade Operations (UKMTO) agency said.
Iran's paramilitary Revolutionary Guard claimed the attack, as well as two other attacks on ships in the waterway.
UKMTO said on X the incident occurred about 15km north-east of Limah, Oman.
Iran has demanded ships use a route along its coastline through the Strait of Hormuz and has repeatedly said that only the route designated by Tehran is safe.
Meanwhile, Yemen's Houthi rebels said they will impose a naval blockade on Saudi Arabia, opening a potential new front against the US in its war with Iran and raising the threat to global energy supplies and trade.
The Iran-aligned Houthi movement made their announcement despite signs that Iran and the United States want to resume diplomacy to halt a worsening cycle of attacks that has all but wrecked a fragile interim agreement signed last month.
Oil prices rose briefly after the Houthi statement but later fell back as traders held out hope of a diplomatic breakthrough.
Iran had been pressing the Houthis to close the Bab el-Mandeb gateway to the Red Sea if the US continued to attack Iranian power infrastructure.
The full closure of the Bab el-Mandeb strait would reduce global oil supply by seven per cent as it would leave most of Saudi oil exports unable to leave the region.
The disruption would add to the huge cut to oil flows from the war in the Gulf, which has already reduced shipments by 10 per cent of global supply.
In their statement, the Houthis' armed forces said they were declaring "a maritime embargo against the criminal Saudi enemy, based on the equation of 'an eye for an eye', effective immediately" in response to what they called "an unjust and oppressive siege" imposed on Yemen by Saudi authorities.
A senior Iranian official told Reuters that Iran had received a proposal from mediators for a 10-day ceasefire in efforts to salvage the interim deal, intended to pave the way to a lasting agreement to end the war that began on February 28 with US-Israeli attacks on Iran.
Prior to the latest round of attacks, President Donald Trump took to social media to warn that "Every time Iran kills an American Soldier they will pay for that killing many times over!"
Trump was planning to attend a ceremony on Tuesday evening at Dover Air Force Base, where at least one service member's remains were due to arrive.
with AP, EFE and DPA
