Has Iran modified its rocket systems to fire mines into the Strait of Hormuz?
The motive behind theUS strikes on Sunday, which hit Iranian rocket launchers on Larak Island in the Strait of Hormuz, appears to have been the prevention of a new threat to shipping in the vital waterway.
Officially, the US military decided to resume its strikes after a month-long hiatus because Iranian forces from the Islamic Revolutionary Guard Corps (IRGC) were preparing to “launch rockets loaded with sea mines into the strait.”
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Rocket launchers as mine launchers
Some maritime security experts say they were taken by surprise by the US's claim.
“This alleged new capability by the Iranians to deploy mines into the strait is puzzling,” said a specialist in maritime conflicts who preferred to remain anonymous.
Since the conflict with the United States and Israel began, Iranians have typically transported sea mines in small, fast boats and then scattered them across the Strait of Hormuz. This has made the strait extremely dangerous as vessels have had to navigate it not knowing the exact location of the underwater explosives.
Sea mines have also been delivered typically by small submarines or dropped by aircraft flying at very low altitudes.
They can be positioned on the seabed or moored above it – or left just beneath the surface of the water where they detect passing ships before exploding on contact with a vessel.
A not so new novel method?
According to Dirk Siebels, a maritime security specialist at Risk Intelligence, using land-based rocket launchers to shoot sea mines into the Strait of Hormuz “would, as far as I know, be a novel method”.
Harlan Ullman, a former US Naval officer, agreed. In an interview with Al Jazeera, he said it was “unlikely” rocket launchers would be used to fire mines because they would be “highly likely to be damaged upon impact with the water,” he said.
However, reports have been circulating for several months about Iran's capacity to use missiles to lay sea mines.
Iranian state television broadcast a report on the Fajr-5 Multiple Launch Rocket System (MLRS) as early as January 2025, referring to it as the newest weapon for mining in the Strait of Hormuz.
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“Iran has been conducting tests with Fajr-5 multiple rocket launchers for this purpose for some time now,” said Sidharth Kaushal, an expert on the impact of new technologies on naval warfare at the Royal United Services Institute for Defense and Security Studies (RUSI), one of Britain's leading strategic think tanks.
A quicker way to deploy sea mines
In principle, weapons can be used to deploy mines.
“Missiles carry the explosives and drop them over the target area,” said Mark Hilborne, an expert in aviation and space security at King's College London.
“The impact can be minimised by equipping the mines with small parachutes, for example.”
If Iran has indeed begun launching mines into the strait using Fajr-5 systems, it would greatly undermine the rhetoric from US President Donald Trump and the Pentagon, who have boasted of having “completely destroyed the Iranian navy”.
For Iranians, “this would be a way to demonstrate their ingenuity and their ability to overcome the destruction of their fleet by the Americans,” explained Shahin Modarres, an Iran specialist at the International Team for the Study of Security (ITSS) in Verona.
And it would give the Iranian regime yet another advantage. “It's also faster. Using a boat requires loading the mines, assembling the crew, travelling to the site, and dropping the mines. With a rocket launcher, all you have to do is load and fire,” Kaushal said.
Time saved can make all the difference.
“It limits the opportunities the Americans have to detect and prevent a threat,” the RUSI analyst added.
Despite its strategic merits, the rocket system is not a panacea. There are practical reasons why using boats is preferable. First, it's possible to carry more mines on a boat.
“A naval mine is a fairly large and heavy warhead because it must be powerful enough to damage a ship's hull. It's difficult to fit many of them into a single rocket launch, because to travel a long distance, the warhead must be lightweight,” Kaushal explained.
Second, rocket-launched mines are not particularly precise compared to other methods. The rocket system tends to scatter mines once they have been fired, making it difficult even for the Iranians themselves to ascertain their location.
Propaganda or a veritable escalation?
Siebels considers the military tactic “rather reckless”, suggesting that Iran would be shooting itself in the foot because “Iranian cargo ships also need to know exactly where the mines are in order to avoid them.”
Without knowing the whereabouts of these mines, it is impossible to guarantee ships safe passage through the strait, even if they have paid the transit fee Tehran is demanding.
Siebels said he is doubtful that rocket launchers are being used. Despite the drawbacks of naval missions – particularly the risk to crews – these more traditional methods would align more with Iran's overall strategy in the Strait of Hormuz.
Others share his scepticism.
“It's war propaganda,” argues Christian Bueger, a specialist in maritime security issues at the University of Copenhagen.
He said he believes that the United States needed to find a new threat to maritime traffic to “justify the strikes” and to reassure shipping companies.
“The United States is seeking to demonstrate that the mine threat is under control,” Bueger said.
Regardless, it cannot be ruled out that laying mines is part of the psychological warfare being waged by these military rivals. With their January 2025 video touting the new capabilities of the Fajr-5, the Iranians sought to demonstrate that they could still wreak havoc in the Strait of Hormuz – whether it is true or not.
“The advantage of mines is that the mere risk of their existence may be enough to discourage ships from passing through the Strait of Hormuz,” Bueger said, adding that the official response by the US to the bombings on Larak Island would be justified because of Tehran's actions in the strait.
Modarres is less convinced.
“The use of rocket launchers is typical of how Iran employs unconventional methods to thwart enemy plans.”
Confronted by Washington's declaration of an all-out economic war, he said Iran may want to demonstrate that it is still capable of imposing its military might over the Strait of Hormuz, blindsiding the Americans by wielding a new weapon to disrupt the vital maritime route.
Whatever the reality – whether bluff and psychological warfare or a veritable threat to the strait – this latest development in the intransigent conflict between Iran and the US reveals that, in an era where drones and AI-enhanced warfare dominate, the threat of mines remains highly effective.
This article has been adapted from the original in French by Nicole Trian.