Iran’s Revolutionary Guards (IRGC) said no commercial vessel or tanker had crossed the Strait of Hormuz in the past few hours, the semi-official Tasnim news agency reported on Monday.

The IRGC called the claims by US officials “baseless and complete lies.”

Earlier on Monday, the US military said two US Navy guided-missile destroyers had entered the Gulf to break an Iranian blockade and that two US merchant ships had ​transited the Strait of Hormuz, after Iran said it had prevented a US warship from entering the Gulf.

US Central Command said its forces were supporting President Donald Trump’s “Project Freedom”, which aims to “guide out” commercial ships ‌stranded in the Gulf by the US-Israeli war on Iran, and were enforcing a blockade of Iranian ports.

The intervention appeared to raise the risk of a confrontation between the US and Iran in a waterway that usually carries a fifth of the world’s seaborne oil and gas but has been blocked for two months as a result of the war.

CENTCOM said two US-flagged merchant vessels had crossed through the strait as the US destroyers operated in the Gulf, adding: “American forces are actively assisting efforts to restore transit for commercial shipping.”

Shipping industry awaits clarity on safety of Hormuz

Oil prices had jumped 5% on reports of the ⁠warship being turned back, but later gave up half of that.

Treasury Secretary Scott Bessent told Fox News that the US had absolute control of the strait.

But the shipping industry remains to be convinced that the vital oil route, whose closure has ​damaged global business and trade, is safe to use, with little sign of progress towards a negotiated resolution of Washington’s conflict with Iran.

Iran’s navy said it had prevented “American-Zionist” warships from entering the Strait area with a “swift and decisive warning”.

Trump gave few details of his ​plan to aid ships and their crews who have been confined to the Gulf 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,” he said in a post on his Truth Social site on Sunday.

In response, Iran’s unified command told commercial ships and oil tankers:

“We have repeatedly said the security of the Strait of Hormuz is in our hands and that the safe passage of vessels needs to be ​coordinated with the armed forces …

“We warn that any foreign armed forces, especially the aggressive US Army, will be attacked if they intend to approach and enter the Strait of Hormuz.”

Iran has blocked nearly all shipping into and out of the Gulf ​apart from its own since the start of the war, sending oil prices soaring by 50% or more.

CENTCOM said it would support Trump’s “Project Freedom” with 15,000 military personnel and more than 100 land- and sea-based aircraft, plus warships and drones.

It was not immediately clear how the operation ‌would work. It ⁠will not necessarily include naval escorts of commercial ships, Axios reporter Barak Ravid said on X.

The White House did not immediately respond to a request for comment. Trump said any interference with the US operation would have to be “dealt with forcefully”.

Hundreds of Merchant ships stuck in Gulf for months

However, the Joint Maritime Information Centre, led by US maritime forces based in Bahrain, told operators in a note that the US had “established an enhanced security area to support Strait of Hormuz transits”.

It advised vessels to use Omani waters on the west of the strait to avoid mines, urging them to “carefully review risk assessments and routing ahead of transit”.

Hundreds of commercial vessels and as many as 20,000 seafarers have been unable to transit the strait during the conflict, the International Maritime Organisation ​says.

The container shipping group Hapag-Lloyd said on Monday that it ​considered that transit through the strait was still not ⁠possible.

Shipping and oil executives have said they need an agreed and full end to hostilities because military convoys alone are not enough to allow normal traffic to resume safely.

The United Arab Emirates on Monday accused Iran of attacking an empty crude oil tanker belonging to the Abu Dhabi state oil firm ADNOC with drones as it attempted to pass through the strait.

In a rare ​piece of good news, Pakistan said the US had handed over 22 crew from an Iranian container vessel that American forces seized last month.

Pakistan, which has been trying to broker ​a peace deal, described the move ⁠as a “confidence-building measure”.