President Donald Trump has said that the US will help guide stranded vessels out of the Strait of Hormuz from Monday.

"For the good of Iran, the Middle East, and the United States, we have told these Countries that we will guide their Ships safely out of these restricted Waterways," he wrote on social media, without specifying which countries would receive assistance.

Trump said any interference in the process, which he called "Project Freedom", will "have to be dealt with forcefully".

Iran has severely limited traffic through the vital shipping waterway since the war began in February. The US has also enforced a naval blockade on Iranian ports.

Senior Iranian lawmaker Ebrahim Azizi, a former commander in Iran's Islamic Revolutionary Guards Corps, wrote on social media that "any American interference" would be "considered a violation of the ceasefire".

In Trump's post, he also said that US representatives were having "very positive" discussions with Iran, and that those talks "could lead to something very positive for all".

Trump added the operation would be a "humanitarian gesture" made on behalf of the US, Iran and other Middle Eastern nations, without listing which countries. He did not provide further details on how co-operation with Tehran would be managed.

"In all cases, they said they will not be returning until the area becomes safe for navigation, and everything else... The Ship movement is merely meant to free up people, companies, and Countries that have done absolutely nothing wrong," Trump continued.

US Central Command said that 15,000 personnel, guided-missile destroyers and more than 100 aircraft would be involved in "Project Freedom".

An estimated 20,000 sailors have been trapped in the Gulf since the start of the war with Iran. There has been growing concern over dwindling supplies and the effects on sailors' physical and mental health.

About 20% of the world's oil and liquefied natural gas (LNG) usually passes through the strait and the conflict has sent global energy prices soaring.

Late on Sunday, the United Kingdom Maritime Transportation Operation (UKMTO) reported that a tanker had been hit by an "unknown projectile" in the strait, adding that the crew were safe.

Trump's announcement came after Iranian state-linked media said Tehran had received a US response to its latest peace proposal.

Iran said the response, delivered via Pakistan, was being reviewed, according to Iran's semi-official Tasnim news agency.

The US is yet to formally confirm it has replied to Iran. However, Trump reportedly told Israel's Kan News on Sunday that the proposal was unacceptable to him.

Iranian state media said Tehran's 14-point peace plan asked for Washington to withdraw its forces from near Iran's borders and end its naval blockade of Iranian ports, and for all hostilities to cease - including Israel's offensive in Lebanon.

It also called for an agreement between the two countries to be reached within 30 days.

Iranian state media added that the proposal urged the two warring sides to focus on "ending the war" rather than extending a current ceasefire.

Iranian foreign ministry spokesman Esmaeil Baghaei was quoted by state media as saying that "at this stage, we do not have nuclear negotiations" - a key demand by Washington.

Iran has repeatedly denied it is seeking a nuclear bomb and says its programme is only for peaceful purposes, though the country is the only non-nuclear-armed state to have enriched uranium at near weapons-grade level.

On Saturday, Trump confirmed that Washington had received the latest Iranian peace proposal.

In a post on Truth Social, he wrote that he would review the plan, but that he "can't imagine that it would be acceptable in that they have not yet paid a big enough price for what they have done to Humanity, and the World, over the last 47 years".

Speaking to reporters later on Saturday, he said he had been told "about the concept of the deal", adding: "They're going to give me the exact wording now."

Asked by the BBC about whether military strikes against targets inside Iran could be renewed, Trump said it was "a possibility".

"If they misbehave. If they do something bad," he said. "But right now we'll see."

The US president appeared disinclined to withdraw from the conflict entirely, saying "we're not leaving" and "we're going to do it, so nobody has to go back in two years or five years".

The Iranian state-linked agencies said Tehran's latest proposal was in response to a nine-point US plan, which envisaged a two-month ceasefire.