How the US can respond as Iran effectively halts cargo traffic in the Strait of Hormuz
US missiles are hitting Iranian Revolutionary Guard Corps (IRGC) fast-attack craft after intelligence suggested that Tehran was beginning a long-expected plan to mine the Strait of Hormuz.
The Islamic Republic has vowed to block the region's oil exports, saying it would not allow "even a single litre" to be shipped to its enemies, despite President Trump threatening to unleash "death, fire and fury" on Iran if it meddles with the flow of oil in the Middle East.
The Strait of Hormuz is a narrow waterway south of Iran and one of the world's most important trade routes – through which a fifth of global oil and seaborne gas is shipped from production facilities and refineries in the Gulf to buyers around the world.
Iran's multilayered threat to shipping
The IRGC has fast-attack craft and previously fired rockets or planted explosives on the sides of ships sailing through the Strait of Hormuz.
From the Iranian coast, the IRGC can launch anti-ship missiles and guided one-way attack drones.
The Iranians can also attack with unmanned surface vessels and underwater drones in kamikaze strikes.
With ships transiting within just 15 miles of the Iranian coast in the strait, reaction times can be very short.
US countermeasures
To counter these threats, Iranian air defences need to be suppressed so US aircraft can operate freely.
The airspace then needs to become saturated with eyes in the skies, including AWACs and maritime surveillance aircraft, but these are vulnerable, and it only takes one Iranian missile to get through.
The US also has Triton or Global Hawk drones, which can stay up for 30 hours at a time and scan vast areas of ocean, although these have been shot down before.
To stop sea drones and IRGC fast attack craft, the US could use Apache helicopters and Reaper drones, as they have done in the Caribbean.
Warships accompanied by mine-hunting drones could then patrol the strait to check that tankers can transit securely.
Previously, the US and UK have carried out these convoy duties, but that was before there was a full-blown war in the Gulf.
Ultimately, though, there is only so much that can be done from the sea and the air.
They need to convince the shipping owners and insurers that the risk is manageable before tankers can move again.
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