US-Iran-Israel: Why is the Strait of Hormuz Closed Again?
For a brief window on Friday 17 April, it seemed as though one of the world's most important shipping lanes might be returning to something approaching normality.
The cost of a barrel of Brent crude fell to US$88 a barrel after Iranian Foreign Minister Abbas Araghchi announced that "the passage for all commercial vessels through Strait of Hormuz is declared completely open for the remaining period of ceasefire," having been above US$98 earlier that day.
Global markets rallied around that announcement, with the S&P 500 closing up 1.2%, while the CAC in Paris and DAX in Frankfurt both ended the day around 2% up.
That moment of respite in what is becoming a protracted energy crisis did not last, however.
Iran closes the Strait of Hormuz again
Within 24 hours, Iranian officials had reversed the reopening and reimposed restrictions on the vital shipping lane after the US said it would not end its blockade of Iranian ports.
Iran's Khatam al-Anbiya joint military command said Tehran had restored the strait to its "previous status" and was now "under strict management and control by the armed forces".
The IRGC did not mince words on what would follow.
"Approaching the Strait of Hormuz will be considered co-operation with the enemy, and the offending vessel will be targeted," the corps warned.
Iran said the restrictions would remain if Washington did not "ensure full freedom of navigation for vessels travelling from Iran to destinations and from destinations to Iran".
Ships under fire
The rhetoric was quickly followed by action.
The UK's Maritime Trade Operations Centre reported that Islamic Revolutionary Guard Corps ships had fired at a tanker as it attempted to pass through the strait on Saturday, while Reuters reported an Indian-flagged vessel carrying crude oil had also been attacked while in the waterway.
India's foreign ministry said it had summoned the Iranian ambassador to convey its “deep concern at the shooting incident earlier today involving two Indian-flagged ships in the Strait of Hormuz”.
A container ship was also struck by an unknown projectile off the northeast coast of Oman, damaging some containers, according to the UK Maritime Trade Operations Centre.
Before Iran's decision to reclose the strait, at least eight oil and gas tankers had passed through the strait in the brief window when it was open early on Saturday, according to maritime tracking data.
Why it matters
Around 20% of the world's oil and LNG ordinarily passes through the narrow strait, which has become a focal point of the US-Israeli war on Iran, and its closure has driven up energy prices around the world.
The closure has also cut off a major supply line of fertiliser used by farmers, with a third of the world's key fertiliser chemicals passing through the strait, raising the prospect of higher food prices. Helium exports have also been majorly affected.
Kieran Tompkins, Senior Climate & Commodities Economist at Capital Economics, has said that even when it was briefly open, the ceasefire “offers only a narrow window of opportunity for oil tankers to navigate the strait, load up, and exit”.
Even the shipping industry was sceptical during the brief reopening.
One oil and gas shipping operator told the BBC it "doesn't change anything" immediately. "We don't feel like we need to be taking unnecessary risks and our company approach is that we won't be the first to go through the strait," they added.
What comes next
Only three ships crossed the Strait of Hormuz on 20 April, according to data from Kpler, after just one made it through the day before. Before the war, the average was more than 120 vessels per day.
Iran's Foreign Ministry Spokesperson Esmail Baghaei confirmed on Monday that Tehran has no plans for a new round of talks with the US, telling Al Jazeera that Washington has violated the ceasefire agreement from its very implementation.
Esmail Baghaei also said that Tehran cannot forget that both the current US-Israeli war on Iran, which began on 28 February, and the 12-day war last year were launched while Iran and the US were actively engaged in talks over Iran's nuclear programme.
He described the US proposals as "unserious" and its demands "unrealistic", adding that Tehran does not believe in ultimatums.
Trump, meanwhile, told Fox News on Sunday that the deal on offer – requiring Iran to reopen the strait and relinquish enriched uranium – was a "very fair and reasonable deal", and vowed to knock out "every single Power Plant" and "every single Bridge" unless Tehran accepted.
The dispute over the strait now extends beyond its immediate closure, with Iranian authorities demanding the right to impose tolls on vessels transiting the waterway – even after any eventual peace deal – a condition the US says it will not accept.
The effective closure of the strait has sent global energy prices soaring and prompted countries to implement fuel rationing and place restrictions on electricity consumption.
For now, with talks stalled and both sides hardening their positions, the world's most important oil chokepoint remains caught between two intractable forces.