U.S. Central Commanded tweeted on Sunday afternoon:

U.S. Central Command (CENTCOM) forces will begin implementing a blockade of all maritime traffic entering and exiting Iranian ports on April 13 at 10 a.m. ET, in accordance with the President’s proclamation.

The blockade will be enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas, including all Iranian ports on the Arabian Gulf and Gulf of Oman. CENTCOM forces will not impede freedom of navigation for vessels transiting the Strait of Hormuz to and from non-Iranian ports.

Additional information will be provided to commercial mariners through a formal notice prior to the start of the blockade. All mariners are advised to monitor Notice to Mariners broadcasts and contact U.S. naval forces on bridge-to-bridge channel 16 when operating in the Gulf of Oman and Strait of Hormuz approaches.

In March, Kelly A. Grieco and Marie-Louise Westermann wrote:

It would be a mistake to read Iranian minelaying as the last act of a cornered adversary. It is a sign of preparation, not desperation — a deliberate effort to shift the terms of the conflict. Tehran is executing a classic risk strategy, exploiting the possibility of escalation to impose global economic costs and generate political pressure on Washington to stop fighting.

The sea mine is the ideal weapon for this strategy. In the Strait of Hormuz — just 21 miles wide at its narrowest point — even a small minefield poses a significant threat, producing global economic impacts far beyond the mines’ immediate physical presence. The roughly dozen mines reportedly laid so far signal Iran’s willingness to escalate, deploying weapons that are difficult to remove and capable of sustaining disruption over time.

Iranian strategy should not come as a surprise. A declassified 2009 CIA report noted that Iran “has adopted a strategy in which a few mines or the threat of mining would be used to deter shipping,” adding that such mining would be “just as effective as a blockade.” A 2017 Office of Naval Intelligence assessment went even further, concluding naval mines were a critical component of the IRGCN’s strategy in the Strait of Hormuz, and that Iran has specifically invested in new mines and mine delivery vessels after observing their impact during the Tanker War and Operation Desert Storm. This is a strategy Iran has planned for decades. Only now has it been put into practice. [Continue reading…]

In March, the Wall Street Journal reported:

Mines have been among the most destructive weapons that the U.S. Navy has faced, maiming more ships than any other means of attack since World War II, according to a U.S. Naval Institute report produced several years ago.

The U.S. military said it has destroyed Iranian naval vessels designed for setting mines. The military earlier said it eliminated an Iranian Kilo-class submarine, which was also thought to have the capability to launch mines.

Yet Iran primarily sets mines using frogmen on small boats that resemble ordinary fishing vessels, an informal maritime militia of dinghies that is virtually impossible to identify and eliminate.

Iran also has an arsenal of limpet mines that divers can attach to the hulls of ships. [Continue reading…]