Concerns are rising over the security of the Strait of Hormuz after US officials said Iran may be preparing to deploy naval mines in the key waterway that carries roughly one-fifth of the world’s oil supply.According to people familiar with US intelligence reporting cited by CNN, Iran has already laid a limited number of mines in recent days, though the deployment is not extensive yet. The sources said only a few dozen may have been placed so far, but Iran still retains most of its fleet of small boats and minelayers, meaning it could potentially deploy hundreds more.

In response, the US on Wednesday carried out strikes to destroy multiple Iranian naval vessels including minelayers near the Strait of Hormuz.Separately, US intelligence estimates cited by Reuters suggest Tehran may possess as many as 6,000 naval mines, including drifting, limpet, bottom and moored mines.The issue has drawn warnings from US president Donald Trump, who said on Truth Social that Washington had no confirmation that mines had been deployed but demanded their removal if they had been placed.“If Iran has put out any mines in the Hormuz Strait, and we have no reports of them doing so, we want them removed, IMMEDIATELY!” Trump wrote, adding that failure to do so could lead to consequences “at a level never before seen.”

Why the Strait of Hormuz matters

The Strait of Hormuz lies between Iran and Oman and serves as the main shipping corridor for crude oil exports from Gulf producers such as Iraq and Kuwait.

About 20% of globally traded oil passes through the narrow waterway each day. According to reports cited by CNN, nearly 15 million barrels per day of crude and another 4.5 million barrels per day of refined fuels could be affected if shipping is disrupted. Because of its narrow transit lanes and shallow waters, analysts say the strait is particularly vulnerable to mine warfare.“Floating and naval mines pose a severe asymmetric threat in these confined waters, particularly in the Strait of Hormuz’s narrow transit lanes,” Scarlett Suarez, senior intelligence analyst at UK-based maritime risk firm Dryad Global, told Reuters.

What are naval mines?

Naval mines are explosive devices placed underwater to damage or destroy ships. They are widely used in naval warfare because they are relatively inexpensive and difficult to detect.According to the Robert Strauss Center for International Security and Law, mines can contain anywhere from around 100 pounds to more than 2,000 pounds of explosives and can be deployed in both defensive and offensive roles.Military forces use mines to block access to waters, damage naval vessels or force ships into specific routes where they are easier to target.Compared with many modern weapons, mines are relatively cheap. Some simple contact mines can cost as little as about $1,500, making them attractive tools for asymmetric warfare.

Types of naval mines

Naval mines vary depending on how they are positioned and triggered.Moored mines:These mines are tethered to the seabed or a weight and float below the surface. They are often deployed in minefields and detonate when a ship comes into contact with them.

Drifting mines:These float freely on the water surface and move with currents. Because they do not remain in fixed positions, they can be harder to track and neutralise.Limpet mines:These are attached directly to a ship’s hull using magnets and are typically detonated using a timed fuse.Bottom mines:These rest on the seabed and are often triggered by sensors detecting a ship’s acoustic, magnetic or pressure signature.More advanced mines can detect specific vessel signatures and explode without direct contact.

How mines are deployed

Mines can be laid using various platforms including naval vessels, submarines, aircraft or smaller boats.Large naval ships are traditionally used to lay mines, but smaller craft can also deploy certain types of mines, making the tactic harder to detect.Iran’s naval forces, particularly the Islamic Revolutionary Guard Corps (IRGC), maintain fleets of small fast boats capable of deploying mines, analysts say. Submarines can also deploy mines using torpedo tubes.According to CNN, the IRGC could potentially deploy a “gauntlet” of mine-laying craft, explosive boats and coastal missile systems to threaten shipping in the strait.

How mines damage ships

When a mine detonates underwater, the explosion generates both a shock wave and a rapidly expanding gas bubble.The shock wave can damage a ship’s hull, electronics and mechanical systems, while the rising gas bubble can destabilise a vessel by lifting or bending its structure.The extent of damage depends on factors such as the size of the explosive charge, the depth of the mine and the type of ship involved.

Why mines could be effective in Hormuz

The geography of the Strait of Hormuz makes it particularly vulnerable to mine warfare. The narrow shipping lanes mean even a limited number of mines could disrupt traffic or force vessels to avoid certain routes.Even the threat of mines can significantly affect global shipping. A 2009 declassified report from the CIA said Iran could use limited mining or even the threat of mining to deter vessels and increase insurance costs for ships entering the Persian Gulf.“Such mining would be just as effective as a blockade,” the report said.

Historical precedent

Naval mines have historically caused significant disruptions in maritime conflicts.During the Iran-Iraq conflict in the 1980s, Tehran laid mines in the Persian Gulf and the Strait of Hormuz. In 1988, one of those mines severely damaged the US navy frigate USS Samuel B Roberts.More broadly, mines have been responsible for a large share of naval damage in modern conflicts, including operations in the Korean War, the Vietnam War and the 1991 Gulf War.

Current risks

With tensions rising in the region, the possibility of mine warfare in the Strait of Hormuz has raised concerns among governments and shipping companies.Even limited mining could slow or halt traffic through the waterway, potentially disrupting global oil markets and forcing naval forces to launch complex and time-consuming mine-clearing operations.For now, officials say the situation remains fluid, with military and intelligence agencies closely monitoring developments in one of the world’s most critical energy chokepoints.