A tanker has reported being hit by unknown projectiles in the Strait of Hormuz, shortly after US President Donald Trump said the US would start helping free ships stranded in the region.

It followed Iran’s state-run IRNA news agency calling Trump’s announcement part of his “delirium”, and Ebrahim Azizi, head of the Iranian parliament’s national security commission, writing on social media platform X that any interference in the strait would be seen as a ceasefire violation.

“The Strait of Hormuz and the Persian Gulf would not be managed by Trump’s delusional posts!” Azizi wrote.

Trump provided few details about the US plan, which he said would start on Monday (local time) in the Middle East and would ‌aid ships and their crews that have been “locked up” in the vital waterway and are running low on food and other supplies.

“We have told these Countries that we will guide their Ships safely out of these restricted Waterways, so that they ‌can freely and ably get on with their business,” Trump said in a post on his Truth Social site.

Dubbing the missing “Project Freedom”, Trump said his representatives were having talks with Iran that could lead to something “very positive for all”.

Hundreds of ships and as many as 20,000 seafarers have been unable to transit the strait during the conflict, according to the International Maritime Organisation.

US Central Command said it would support the effort with 15,000 US military personnel, more than 100 land and sea-based aircraft along with warships and drones.

It said the operation aimed to “restore freedom of navigation for commercial shipping” through the vital strait.

“Our support for this defensive mission is essential to regional security and the global economy as we also maintain the naval blockade,” Admiral Brad Cooper said.

Soon after Trump’s comments, ‌Britain’s Maritime Trade ‌Operations agency said a tanker had ⁠reported being hit by unknown projectiles in the strait.

It said all crew were reported safe in the incident, which occurred about 140 kilometres north of ​Fujairah, in the United Arab Emirates.

Iran has blocked nearly all shipping from the Gulf, apart from its own, for more than two months, sending energy prices soaring.

Some vessels trying to transit the strait have reported being fired on. Iran has seized several other ships.

In April, the US imposed its own blockade of ships from Iranian ports.

Trump threatened any ⁠interference with the new US operation would “have to be dealt with forcefully”.

Recent strikes and suspicious activity in the Strait of Hormuz. Image: Maritime Trade ‌Operations

Iran said on Sunday it had received a US response ‌to its latest offer for peace ​talks a day after Trump said he would probably reject the Iranian proposal because “they have not paid a big enough price”.

Trump, responding to shouted questions, said on Sunday night that talks were going “very well” without elaborating.

Iranian state media reported that Washington had conveyed its response to Iran’s 14-point proposal via Pakistan, and that Tehran was now reviewing it.

“At ​this stage, we do not have nuclear negotiations,” state media quoted Iran’s Foreign Ministry spokesperson Esmaeil Baghaei as saying, an apparent reference to Iran’s proposal to set aside talks on nuclear issues until after the war has ended and the foes have agreed to lift opposing blockades of Gulf shipping.

On Saturday, Trump said he had yet to review the exact wording of the Iranian peace proposal, but he was ​likely to ​reject it.

Iranian media said Tehran’s 14-point proposal includes withdrawing US ⁠forces from nearby areas, lifting the blockade, releasing frozen assets, paying compensation, lifting sanctions, ending the war on all fronts including Lebanon, and creating a new control ​mechanism for the strait.

-AAP