The latest round of attacks, which the United States said was launched in response to Tuesday's assault on three cargo ships transiting the strait, rattled several cities along Iran's southern coast and left some areas without power.
"US Central Command forces have started conducting additional strikes against Iran to further degrade their ability to threaten freedom of navigation in the Strait of Hormuz," CENTCOM, the US military's Middle East command, wrote on social media platform X.
"The United States is holding Iran accountable for recent unjustified aggression against commercial shipping and civilian crews freely navigating a vital international waterway."
The US strikes on Thursday sparked retaliatory Iranian fire targeting Bahrain, Kuwait and Qatar. There was no immediate word of damage but Kuwait's military said it was actively intercepting incoming drones and missiles.
The strikes against Iran will be greater in number than the ones carried out a day earlier, a US official told Reuters, speaking on condition of anonymity.
"This is in retribution for yesterday's bombing of ships by Iran. If it happens again, it will get much worse!" Trump wrote on his Truth Social platform, posting several videos of what he said were explosions in Iran.
Control of the strait, through which a fifth of global oil supplies pass, has given Tehran immense leverage, effectively allowing it to force a stalemate with the world's most powerful military.
While Iran has not claimed responsibility for the ship attacks, analysts say Tehran uses such actions to create leverage as it negotiates a long-term deal with the US.
Nournews, affiliated with Iran's top security body, cited a military source as saying Tehran would soon launch a "massive attack" on US bases in the region, a threat echoed by a senior adviser to Supreme Leader Ayatollah Mojtaba Khamenei.
"The aggressor enemy and its accomplices will be severely punished," Mohsen Rezaei wrote on X.
The latest escalation dented hopes of turning a memorandum of understanding signed on June 17 into a permanent peace deal to end the war, which began with US-Israeli airstrikes on Iran on February 28.
Asked before a NATO summit in Turkey whether the memorandum of understanding was over, Trump said: "It's a very interesting question. To me, I think it's over. I don't want to deal with them.
"If we make a deal with Iran I'm not sure that will stick," Trump later said.
"I found them to be very dishonourable people."
But Trump, who has repeatedly threatened to escalate military action before backing off, said he did not expect a return to full-fledged war, and it was not clear whether the negotiations on reaching a permanent deal would continue.
"Anything that happens is going to be over very quickly ... and will only make it safer, including for oil," he said.
Iranian media reported strikes primarily along Iran's southern coast, from the Strait of Hormuz to the Gulf of Oman.
Among the locations hit were Bandar Abbas, home to Iran's largest port and key navy and Revolutionary Guards facilities on the Strait of Hormuz, as well as Konarak and Chabahar, neighbouring coastal cities near Iran's border with Pakistan.
Prior to the fresh US attacks, Iranian Foreign Ministry spokesperson Esmaeil Baghaei had said American strikes had violated the memorandum by challenging a clause that "emphasises the Islamic Republic of Iran's responsibility in determining arrangements for the safe passage of ships through the Strait of Hormuz".
with AP
