Donald Trump has stepped up pressure on Nato allies to help reopen the Strait of Hormuz as the US-Israeli war in Iran enters its third week.
Iran’s effective blockade on the key waterway has seen the price of oil soar above $100 per barrel, as countries avoid transiting through the Strait.
Concerns around oil shortages as a result of the closure have grown severe that over 400 million barrels of oil from the International Energy Agency's emergency reserves are set to be released in a bid to counter a price surge.
Speaking to the Financial Times, the US president said: “It’s only appropriate that people who are the beneficiaries of the strait will help to make sure that nothing bad happens there. If there’s no response or if it’s a negative response, I think it will be very bad for the future of Nato.”
Ships continue to face attacks in the Strait. The UK Maritime Trade Operations Centre (UKMTO) has received 16 reports of attacks on vessels operating in and around the Arabian Gulf, Strait of Hormuz (SOH), and Gulf of Oman since 28 February.
Meanwhile, former head of strategy at BP Nick Butler has said UK ministers should be preparing for a “significant shortfall of supply over the next two months”.
He said this could involve “a form of rationing”, adding: “I think we learnt from the tanker drivers dispute in 2000 that oil and gas supplies are absolutely crucial to the running of the economy and you can’t bring on new supplies quickly.”
The Islamic Revolutionary Guard Corps navy had declared “complete control” of the Strait on Wednesday 4 March, days after US-Israeli strikes took out the Islamic Republic’s supreme leader Ayatollah Ali Khamenei on 28 February.
The IRGC threatened to set fire to any ships attempting to pass through the strait.
Below, we look at why the strait is so strategically important and what impact the war is having so far.
Where is the Strait of Hormuz?
The Strait of Hormuz lies between the Persian Gulf to the north and the Gulf of Oman to the south, opening up to the Arabian Sea and beyond to the rest of the world.
It is roughly 100 miles long, but only 21 miles across at its narrowest point.
The land-flanked passage lies in Iran’s territorial waters, but is viewed as an international waterway and is normally open to all ships. It consists of two shipping lanes allowing traffic to pass in opposite directions, each two miles wide, with another two-mile-wide lane separating them.
International law permits countries to exercise control up to 13.8 miles (12 nautical miles) from their coastline. At its narrowest point, the passage comes under both Iranian and Omani control.
Iran lies on one side of the strait, and some of the world’s biggest oil suppliers including Kuwait, Bahrain, Qatar, the UAE, Saudi Arabia and Oman lie across the waters.
What passes through the strait?
It is one of the world’s most important maritime chokepoints, with 20 million barrels of oil passing through it each day – one-fifth of global oil consumption – and up to one-third of the world’s supply of liquefied natural gas.
This amounts to over 500 million barrels of oil and 6 million tonnes of gas every month, according to Lloyd’s List. Much of this is exported to Asian markets, including China (Iran’s only remaining oil customer), India and Japan.
It is the route used by supertankers carrying oil and gas from Saudi Arabia, Kuwait, Iraq, Qatar, Bahrain, the UAE and Iran.
MORE | US & Israeli Air Campaign 🧵(1/3): Iranian mining efforts are part of a broader Iranian effort to disrupt maritime traffic in the Strait of Hormuz and the Persian Gulf to try to impose a cost on the Gulf states and the United States. Iranian efforts to mine the Strait of… https://t.co/MkfgjuCHFz pic.twitter.com/KPJETgzxiw
— Institute for the Study of War (@TheStudyofWar) March 11, 2026
Around 3,000 shipping vessels pass through the passage every month, including oil tankers, liquefied natural gas containers, and cargo vessels, according to Lloyd’s List. This amounts to more than 30,000 ships every year.
While there are pipelines in Saudi Arabia and the UAE that can transport oil, the US Energy Information Administration says that “most volumes that transit the strait have no alternative means of exiting the region”.
On 18 February, Iran closed the Middle Eastern waterway for the first time since the 1980s as Iranian troops took part in live-fire military exercises.
Iran had not threatened to close the passage even during its 12-day war with Israel last June, when US-Israeli strikes took out some of the country’s key nuclear and military sites.
A global trade bottleneck as missiles rain down
Passage through the waterway has almost ground to a halt, creating a trade bottleneck, since the war broke out.
The number of oil tankers crossing the strait was at 20 per cent of pre-war levels on Monday, according to a Goldman Sachs analysis using ship-tracking data from S&P Global and Kpler reported in the Wall Street Journal.
Goldman Sachs estimates that there has been a slight uptick in traffic over the last week but that vessels only carried around 1.6 million barrels through the waterway each day, a fraction of the 20 million barrels pre-conflict.
Kpler reported on Tuesday last week that it “can say with near certainty that seven vessels, including four tankers and three bulk carriers, have crossed the Strait of Hormuz since 6 March.”
The UKTMO has received reports of at least 16 attacks on vessels. A US oil tanker was set on fire, while at least one Indian crew member was killed on Sunday 1 March, according to Euro News. Several reports from trade publications suggest that others have been injured.
The war has spilled over into international waters with the US military torpedoing an Iranian warship off the coast of Sri Lanka on Wednesday 4 March. At least 87 people were killed.
Effects on oil prices and the global economy
Any disruption to traffic through the Strait of Hormuz is highly disruptive to the oil trade. Since the outbreak of conflict oil prices have surged to over $100 a barrel.
“The scale of what is at stake cannot be overstated,” said Hakan Kaya, senior portfolio manager at investment management firm Neuberger Berman.
Amin Nasser, the president and CEO of Saudi Arabia’s oil giant Aramco, warned on Tuesday that if oil tankers continue to be unable to transit the strait “that will have a serious impact on the global economy.”
Threats to the route have spiked global energy prices in the past, including during the Israel-Iran war in June 2025.
China and Japan, who will be severely affected, have called for an immediate de-escalation of the conflict.
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