Could Iran use missiles to lay mines in the Strait of Hormuz?

The latest round of fighting between Iran and the United States began on Lark Island, near the shipping lanes of the Strait of Hormuz.

After a pause of nearly a month in US attacks on Iran, US Central Command (CENTCOM) announced that it had targeted two platforms belonging to the Iranian Revolutionary Guard on the island on August 30.

Captain Tim Hawkins, a Centcom spokesman, said members of the Revolutionary Guard were seen preparing to launch “missiles carrying sea mines” into the strait. Iran responded by launching missile strikes on a site housing American forces in Jordan, bringing the two sides back into direct confrontation.

At the heart of this renewed confrontation was a relatively unknown and highly unusual method of laying mines: launching them from the coast with missiles, rather than deploying them from a ship or boat.

The Revolutionary Guard had previously displayed what the Iranian media presented as a capability of this type during a military maneuver. But the attack on Lark Island marked the first time that missile-delivered mines have featured prominently in a direct confrontation between Iran and the United States.

The timing was important, as Centcom had announced just two days earlier that mines planted along international shipping lanes in the strait had been removed.

The Financial Times reported that the operation took four months and was carried out mostly at night, using US Navy divers, robotic boats and unmanned underwater vehicles.

The International Maritime Organization estimated in June that about 80 mines had been planted along vital shipping lanes. President Donald Trump said in late August that all mines in international waterways had been removed or destroyed, although Marine Information Services continued to warn of the possibility of floating or unmapped mines.

Scott Savitz, a senior engineer at the RAND Corporation, told BBC Persian that laying mines requires far fewer resources than removing them, and can be accomplished much more quickly.

He added: "Creating a minefield may take hours, while opening safe passages through a minefield may take days or weeks."

The system, which appears to be the predecessor to the one described by the United States, was unveiled during the “The Greatest Messenger 19” exercise conducted by the IRGC Naval Force in January 2025.

Iranian media broadcast footage showing several missiles being launched from a launch pad mounted on a truck. The video then moved to scenes of cone-shaped objects floating on the surface of the water, which were presented as sea mines.

The Defense Press Agency, an Iranian media outlet linked to the General Staff of the Armed Forces, said that the mines were placed “inside a container similar to Fajr 5 missiles” and were launched from the coast towards specific areas in the sea.

It also claimed that the system is capable of launching “hundreds of mines” into the water within one hour, but did not provide any technical details to support this figure.

The footage showed missile launches and objects floating in the sea. But it did not show, in one continuous sequence, how the payload separated from the rocket or entered the water.

Defense Press said at the time that the new mine belonging to the Revolutionary Guards' naval force possesses capabilities that commanders consider secret.

The US Central Command (Centcom) did not specify the type of launchers that were targeted on Lark Island. Captain Tim Hawkins told the military magazine The War Zone only that members of the Revolutionary Guard were preparing to launch “missiles carrying sea mines.” He did not mention the Fajr 5 missiles.

The connection was made to the Fajr 5 missiles because the mission described by the United States appeared similar to the mine delivery system demonstrated during the Iranian exercise the previous year.

The Fajr 5 is the largest known member of the Iranian Fajr artillery missile family. It was originally developed as an unguided surface-to-surface weapon, and has appeared in several versions and configurations since the 1990s.

According to the specifications published by the Iranian Defense Products Export Center, the standard Fajr 5 missile has a diameter of 333 mm and a length of 6.4 metres. It weighs 907 kilograms, carries a warhead weighing 175 kilograms, and has a declared range of 75 kilometres.

The standard version is usually launched from a truck-mounted four-tube launcher.

The missile has undergone modifications over the years. In February 2017, Iran's Ministry of Defense and Armed Forces unveiled the Fajr 5C, a guided version designed to improve accuracy.

The ministry's export center also described a two-stage version of the missile. Iranian sources estimated its range at between 180 and 190 kilometers.

In 2023, Defense Press reported that a piezothermal warhead had been tested on a Fajr 5 missile. Piezothermal munitions disperse fuel into the surrounding air before igniting, generating intense heat and an extended blast wave.

As for the system that was displayed during the Revolutionary Guard maneuver, it was presented as a further development of the Fajr 5 missile, where the traditional explosive warhead was replaced with a container designated for transporting a sea mine into the water.

The War Zone magazine estimated that the standard missile's range of 75 kilometers is sufficient to reach shipping lanes in the Strait of Hormuz, including the southern route, from parts of the Iranian coast or nearby islands.

The truck-mounted launcher can leave the launch site shortly after the launch, reducing the time available for detection and targeting.

However, the missile's payload carrying capacity will limit the size of the mine. An article published by the Center for International Maritime Security estimated the payload of the Fajr 5 missile at about 90 kilograms, which is less weight than many conventional American and Chinese sea mines.

The author of the article believed that the danger posed by smaller mines lies largely in their use within a group. The presence of several mines scattered along a shipping lane may disable a ship, while causing limited damage to even a small number of commercial ships may prompt shipping companies to change the routes of their ships or suspend their cruises.

Sea mines are typically deployed by surface ships, submarines or aircraft, Savitz told BBC Persian. As for mines dropped from aircraft, parachutes are used to slow their descent.

“In general, sea mines are not launched by missiles, but rather from surface ships, submarines or aircraft,” he said.

He added: "It is difficult to imagine a system that combines a missile and a mine so that the mine does not suffer significant damage upon launch and/or during its entry into the water. It is not impossible in theory, but it is highly unlikely."

The mine carried by a missile will have to withstand the forces resulting from the launch process, and then enter the water without the detonator or other sensitive components being exposed to serious damage.

Harlan Ullman, a retired senior US Navy officer, raised similar doubts in an interview with Al Jazeera. He said that the force of collision with water could cause extensive damage to the mines carried by the missile. He also pointed out that Iran has several other means of planting mines.

An additional drawback, Savitz noted, is that the missile's trajectory and the point where its payload enters the water will be highly visible, making it easier for demining forces to identify the area to search.

He said: “Dropping mines from ships is much more secretive. Even if the ship can be traced, it is difficult to know where the mines may have been planted. But pushing a mine outside the ship only results in a splash of water.”

Savitz believes that the main advantage of laying mines by air, and perhaps also of launching mines by missiles if a practical system can be developed, is the ability to reach areas of water that mine-laying ships cannot safely enter.

He cited the fact that American aircraft planted mines in waters under Japanese control during World War II, and in the port of Haiphong in North Vietnam during the Vietnam War. In both cases, the planes were able to reach areas where it would have been too risky to send mine-laying ships.

“If the United States is successful in preventing Iranian ships from laying mines, Iran may desperately need another way to do so,” Savitz said.

The International Maritime Security Center also believed that missiles or rocket-propelled grenades may allow mines to be laid more quickly and from greater distances, keeping participating individuals away from the minefield.

But currents could push mines away from their intended locations, Savitz said. He added that it "will not pose a sustainable threat in the Strait of Hormuz," and may also endanger ships heading to or coming from Iranian ports.

Savitz said that clearing mines would become much slower and more difficult if the forces carrying out the operation were exposed to missile or drone attacks at the same time. He added that in such circumstances, disinfection may become completely impossible.

He said: "For this reason, the best anti-mine operations are those that prevent those who lay mines from introducing them into the water in the first place, by targeting mine storage sites and the means of laying them."

This was also the justification given by the United States for attacking the launch pads on Lark Island. US Central Command said that its destruction before launch prevented more mines from entering shipping lanes that had been recently cleared.

Savitz explained that ships trying to cross the strait face two separate dangers: mines on or below the surface, and air attacks that include missiles and unmanned aircraft.

He said: "Reducing the risks to a level that allows most commercial shipping traffic to continue requires reducing both threats to acceptable levels."

The 2025 maneuver demonstrated that the Revolutionary Guard included missile-borne mines in its public display of its military capabilities. The Lark strike also showed that the United States views this possibility seriously enough to take action.

But the extent to which this system can work reliably depends on the stages that were not shown in the Iranian footage: the mine separates from the missile, slows down sufficiently, enters the water intact, and remains operational after that. These stages are what distinguish between a military demonstration of a capability and a weapon that can actually be used in the Strait of Hormuz.