What are Iran's 'rocket mines' struck by the US military?

Iran may have developed a new capability to lay sea mines from land using rocket launchers — without deploying ships or submarines. Analysts say the US military's recent airstrike on Iran's Larak Island in the Strait of Hormuz was aimed at preventing exactly that kind of "rocket-deployed mine" from being used.

According to The New York Times, CENTCOM said it detected signs that Iran's Islamic Revolutionary Guard Corps was preparing to fire mine-laden rockets into the Strait of Hormuz during Monday's strike on Larak Island.

CENTCOM Col. Tim Hawkins said forces had detected indications that rockets loaded with mines were about to be launched, and that two mine-laying rocket launch sites were struck as a result. The strike marked the resumption of direct US military action against Iran within a month; Iran subsequently retaliated, ratcheting up tensions in the Strait of Hormuz once again.

Mines are typically deployed by minelayer vessels or submarines, or dropped from aircraft by parachute. Iran is believed to possess a range of mine capabilities, from small limpet mines that divers attach directly to a ship's hull to larger mines capable of sinking major vessels.

The weapon US forces identified, however, is believed to work by loading mines onto rockets and firing them from shore into the sea. If confirmed, it would mean Iran could scatter mines across the Strait of Hormuz from the coastline without sending ships out to lay them directly.

In practice, Iran demonstrated a variant of its Fajr-5 rocket capable of dispersing "single drifting mines" at sea during a military exercise in January last year. The Fajr-5 has a caliber of 333 millimeters, which limits the size of mine it can carry internally; analysts assess it can accommodate small mines carrying tens of kilograms of explosives.

Such a weapon would lack the power to sink a large oil tanker but could pose a serious threat to smaller vessels. Particularly concerning is the use of drifting mines — unlike moored mines fixed to the seabed, drifting mines travel with ocean currents, making their location difficult to predict and threatening civilian shipping. Should they wash ashore, they could also cause casualties.

The New York Times said it could not independently verify the US military's account, but said that if accurate, it would mean Iran had acquired an unusual and previously unseen form of mine-laying capability.