An advisory note from the Joint Maritime Information Centre (JMIC) issues advice, ahead of the US naval blockade on Iranian ports beginning on Tuesday.

The UK's Maritime Trade Operations shared the notice on X, writing that the regional maritime security threat level remains severe.

"Furhter deliberate hostile activity" is likely under current condition, the notice adds.

Mariners should expect a "sustained naval presence, increased IRGC hailing and monitoring along transit routes," and enforced protection measures should be anticipated.

They are told to consider complying with the directions of blockading forces, demonstrating clear transit intentions and report unusual activity.

US Central Command (Centcom) says the Strait of Hormuz blockade will resume at 16:00 ET (21:00 BST) on 14 July.

Earlier, Donald Trump said the blockade would begin "immediately".

"Centcom forces will enforce the blockade against vessels transiting to or from Iranian ports and coastal areas," the US military says in a post on X.

"The US military continues to support traffic flow through regional waters for all vessels not violating the blockade."

It urges all mariners to monitor broadcasts and contact US naval forces when operating in the Gulf of Oman and Strait of Hormuz approaches.

Image source, EPA/Shutterstock

Iran's Foreign Minister Abbas Araghchi has posted a mocking reaction to Donald Trump's announcement that America will impose a charge on cargo passing through the Strait of Hormuz.

"POTUS is absolutely right," he says on X. "Whoever provides secure and safe passage of commercial vessels through the Strait of Hormuz should be compensated for this service."

"Iran has always been the GUARDIAN of the Strait and will remain so FOREVER," Araghchi says.

"20% is of course too much. We will be fair," he adds.

The US president is attending a Grand Prix showcase event with race car drivers at the White House.

We're listening across to Trump's remarks in Washington and will bring you any lines from him that are relevant to Iran.

You can also watch live at the top of the page.

Image source, Reuters

Iran's Foreign Ministry spokesperson Esmail Baghaei has condemned the reported attack on the airport in Yemen's capital, Sanaa, calling it a "blatant violation of international aviation law".

Yemen's armed forces reportedly targeted the runway earlier today to prevent an Iranian aircraft from landing.

Yemen's capital Sanaa is under the control of the Iran-aligned Houthi group, while the internationally-recognised government, which has the backing of Saudi Arabia, operates out of Aden in southern Yemen.

Houthi media subsequently said the Iranian plane had landed anyway.

The details of the incident remain unclear, but it already appears to be the most significant escalation in the largely dormant conflict between the Yemeni government and the Houthis for several years, our correspondent wrote earlier.

Where is Iran’s Supreme Leader?published at 18:44 BST

18:44 BST

Ghoncheh Habibiazad
BBC Persian

Image source, Reuters

Iran’s Supreme Leader Mojtaba Khamenei has not been seen in any verified videos or photos since his succession to the position of his father in early March.

He was reportedly injured in the same strike that killed his father Ali Khamenei on 28 February in Tehran, when US and Israel attacked Iran in the first day of the war. But Iran’s health ministry has rejected claims that his injuries were severe.

US President Donald Trump said about Mojtaba Khamenei today that he’s “90 per cent gone”.

So far, since 8 March, we have seen several written messages attributed to Mojtaba Khamenei. In the latest one two days ago, Khamenei vowed to avenge his father’s killing. Iranian officials have followed suit recently.

Mojtaba Khamenei did not appear publicly during the week-long commemoration ceremonies held in early July for his father, although brothers of Mojtaba Khamenei did.

The question still remains about his whereabouts.

But Israel had vowed before and after Mojtaba Khamenei became Iran’s supreme leader that it would target him, although we are yet to see when, or if, he will appear if public.

If you're just joining us, here's a quick rundown of events this afternoon:

• Donald Trump announced a new blockade on Iranian ports, which will prevent "Iran’s ships or customers" from entering or leaving the Strait of Hormuz

• He added that for doing so, the US will impose a 20 per cent charge "on all cargo shipped" to cover any and all costs of providing "safety and security" in the "volatile" region
• It is not the first time Trump has imposed a blockade on the vital shipping route. The one in April lasted three months, during which the US military fired on at least nine vessels which it said refused to comply with directions
• Trump's announcement followed a fresh round of strikes between the US and Iran overnight. US Central Command (Centcom) said it struck several targets, including a submarine and ship maintenance facility in response to Iranian attacks in the strait
• Responding to the introduction of a new blockade, Iranian parliamentarian Ebrahim Rezaei said: "We don’t need foreign workers to protect the strait!"
• This latest escalation has once again halted traffic through the strait, with two vessels appearing to have sailed east into the Gulf of Oman earlier today. Two other ships stopped transmitting their locations after previously appearing to head out of the strait

Bernd Debusmann Jr
White House reporter

Image source, Getty Images

On one hand, President Trump's announcement that the US will impose a 20% toll on all cargo passing through the Strait of Hormuz is one that, broadly, is in line with his foreign policy.

Trump often remarks that US allies do not pay enough for their own defence or security. The US, he claims, shoulders the financial and logistical burden for global security issues.

Reimbursement for the heavy commitment of US naval and air power to secure shipping in the Gulf is aligned with that sentiment, even if allied nations push back on it.

On the other hand, it directly contradicts recent statements from his own Secretary of State, Marco Rubio.

"No country is allowed to charge tolls or fees on an international waterway," Rubio told reporters in early July.

"That’s existing international law. That’s the way it is in international waterways all over the world, and that’s the way we expect it’ll be here."

Moving forward, the White House is likely to take steps to publicly differentiate between the tolls Trump announced and those that have been called for by the government in Tehran.

The Strait of Hormuz connects the Gulf with the Arabian Sea and is deep enough for the world's biggest crude oil tankers to pass through.

In 2025, about 20 million barrels of oil and oil products passed through the Strait of Hormuz per day, according to estimates from the US Energy Information Administration (EIA).

About 20% of the world's oil and liquefied natural gas is shipped through the strait. The oil comes not only from Iran but other Gulf states such as Iraq, Kuwait, Qatar, Saudi Arabia and the UAE.

About 3,000 ships usually sail through the strait each month but this dramatically decreased during the US-Iran war.

At the narrowest point, the strait and its shipping lanes lie entirely within Iran and Oman's territorial waters - making it a particularly prominent sticking point in the ongoing hostilities.

We've heard from Iranian parliamentarian Ebrahim Rezaei, a spokesperson for the country's National Security and Foreign Policy Commission, following Trump's announcement of a new blockade of Iranian ports.

In response to the US president's assertion that the US will be the "guardian" of the Strait of Hormuz, he writes on X: "We don’t need foreign workers to protect the strait!"

How much oil is thought to have left Iran since the first US blockade was lifted?published at 16:55 BST

16:55 BST

By Thomas Copeland

After the deal to end the war between the US and Iran was signed on 17 June, Washington lifted its two-month blockade of Iranian ports in the Strait of Hormuz.

It also eased decades-old sanctions by allowing for the temporary sale of Iranian oil.

This was due to expire on 21 August but the US withdrew its permission after a series of attacks on ships in the strait early last week.

In the month since the license was issued, 59 tankers left the Gulf laden with oil and petrochemicals, according to United Against a Nuclear Iran, an advocacy and monitoring group.

It says the exports amounted to about 72 million barrels of oil which could provide potential revenue of more than $5.5bn (£4.1bn) for the Iranian government.

Michael Race
Business and economics reporter

US stock markets have fallen in morning trading on Monday as investors react to the escalating situation in the Middle East.

All three of the main indexes, the Dow Jones, Nasdaq and S&P 500, are down amid fears of inflation, with oil prices climbing more than 4% to around $79 (£59) a barrel for Brent crude, the global benchmark.

The US and Iran renewed attacks over the weekend and Tehran said it had closed the Strait of Hormuz, a key waterway used in global trade.

However, President Trump says the strait will remain open and that he will reinstate a blockade on Iranian ports, which he claims will stop "Iran's ships or customers from entering or leaving", but be open for other countries which will be required to pay a 20% cargo charge.

Concerns over global oil supplies since the outbreak of the war have led to prices becoming volatile. While they have risen on the latest news, they remain well below where they were in May.

The US stock markets are also being affected by a tough start to the month for technology and microchip firms, with investors continuing to grapple over high valuations and concerns of an AI bubble. Shares in Nvidia, SpaceX and Intel were all in the red in early trading.

Image source, Centcom / X

US Central Command (Centcom) says, in an update, that American military forces struck a submarine and ship maintenance facility in Iran overnight.

It says multiple one-way attack surface drones hit the port at Bandar Abbas Naval Base in southern Iran, and shares video footage of the operation.

"Last night’s strikes degraded Iran’s ability to continue attacking commercial shipping," Centcom adds in a statement on X.

The US had previously said it conducted its strikes in response to Iranian attacks on commercial ships in the Strait of Hormuz.

What happened during the last US blockade?published at 16:14 BST

16:14 BST

By Thomas Copeland

President Donald Trump first introduced a US naval blockade of Iranian ports three months ago to the day on 13 April, after Tehran effectively closed the Strait of Hormuz in response to US and Israeli strikes on Iran.

The blockade was lifted last month as part of a deal to end the war between the US and Iran.

During the blockade, the US military says it redirected at least 142 commercial ships going to or from Iranian ports and fired on at least nine vessels which it said refused to comply with its directions.

While the Pentagon did publish a blockade line, stretching across the entrance to the Gulf of Oman, US forces intercepted multiple ships well outside of the region too.

A tanker called Tifani, for example, was intercepted east of Sri Lanka more than a week after leaving the Gulf.

Bernd Debusmann Jr
White House reporter

What Donald Trump's latest announcement of a new blockade on Iranian ports means in practice remains unclear.

Many US allies are likely to baulk at the prospect of reimbursing the US and paying 20% of all cargo shipped - and his detractors at home and abroad are likely to point out that the strait was open and unencumbered before Operation Epic Fury began on 28 February.

The announcement could also become politically complicated for the president domestically.

Some lawmakers - including Republicans - had openly questioned what the US gained from the ceasefire, its extension and further negotiations.

Many Americans are also likely to wonder why - despite repeated promises to the contrary - oil prices are inching up again. Trump is not on the ballot for the upcoming midterm elections, but other Republicans are and will be hearing from constituents concerned about prices.

The announcement could also be a bid to restart negotiations and push other countries to be more involved, a tactic that Trump has used in the past.

In a few hours' time we will hear from Trump on-camera, when he may provide more detail about the announcement.

Image source, Reuters

This is not the first time Trump has blockaded Iranian ports in the Strait of Hormuz.

In April, US forces announced they would intercept or turn back vessels travelling to or from Iran's coast. The US wanted to restrict Tehran's ability to profit from oil exports in an attempt to put pressure on the country.

The UN's maritime agency, the International Maritime Organisation, says no country has a legal right to block shipping in straits used for international transit.

"We're not going to let Iran make money on selling oil to people that they like and not people that they don't like," Trump said at the time.

Iran called the move "piracy".

The two countries had agreed to lift the blockade and reopen the Strait of Hormuz in the interim deal - or memorandum of understanding - agreed on June 17.

This time round, Trump has also imposed a charge of 20% on all cargo shipped through the vital waterway, but he did not explain how this would work.

US President Donald Trump has just said the US will reinstate the blockade on Iranian ports.

Here's his Truth Social post in full:

"The Hormuz Strait is OPEN, and will remain OPEN, with or without Iran. We are reinstating the THE IRANIAN BLOCKADE, so named because it is only stopping Iran’s ships or customers from entering or leaving. All other countries will have fair and open use of the Strait.

"The U.S.A. will be, from this point forward, known as 'THE GUARDIAN OF THE HORMUZ STRAIT,' but as such, and as a matter of FAIRNESS, will be reimbursed, at the rate of 20% on all cargo shipped, for any and all costs necessary to do the job of providing safety and security to this very volatile section of the World. The process and formation will begin immediately."

Videos show separate fires near Iranian airport and port on Strait of Hormuzpublished at 15:18 BST

15:18 BST

Image source, Telegram

By Shayan Sardarizadeh and Benedict Garman

A large fire at a hangar at Aghajari Airport in Omidiyeh, south-western Iran, has been captured in footage apparently showing the aftermath of overnight US strikes on Iran.

Multiple videos and still images captured around half a mile east of the airport show the same incident. From that distance it is unclear whether the hangar itself is on fire.

Elsewhere, verified video captured at Suru Beach Park in Bandar Abbas on the Strait of Hormuz shows an orange glow and a plume of black smoke rising in the direction of Shahid Bahonar Port, south-west of the city.

In another statement shared on Tasnim news agency, a spokesman for Iran's Islamic Revolutionary Guard Corps says the US has "seriously jeopardised the security of global oil and gas supplies" by interfering in the Strait of Hormuz.

The statement adds that Iran continues to control the strait and "will force foreign powers and their allies to submit to the will of the Iranian people".

"We will bring them [the US] to even greater humiliation and despair in their new acts of aggression," it says.

Oil prices jumped at the start of trading this morning after the latest tit-for-tat attacks, but remain significantly below the peak seen at the height of the conflict.

Iran's top military headquarters, Khatam al-Anbiya, says it will not allow the US to "interfere in the management" of the Strait of Hormuz.

In a statement shared by Iran's Tasnim news agency, the Iranian military says "frequent misadventures" from the US in the strait have "seriously jeopardised the security of the region".

It adds "we do not and will not allow" the US to control the crucial waterway - and that Iran's armed forces are dealing with any disturbances from the "bandit army" of the US.

Any cooperation with the US will be considered an act of "war" against Iran's sovereignty, it adds, warning that if the conflict spreads "the flames of war will engulf all the countries of the region".

Earlier today, Donald Trump said the US was "taking over the strait".