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Policy Analysis

PolicyWatch 1987

Political-Military Challenges of Demining the Strait of Hormuz

Michael Knights

Also available in العربية

September 28, 2012

Given Iran's clear rhetorical and military threats to Gulf shipping, the United States and its allies must step up their efforts to improve countermine capabilities and publicly signal the regime against any naval provocations.

Over the past week-and-a-half, nearly thirty nations participated in the International Mine Countermeasures Exercise (IMCMEX) in the Persian Gulf, which concluded yesterday. Following up on strong U.S. Navy reinforcement efforts in the Gulf, IMCMEX signaled Iran that there is significant multilateral resolve to keep the Strait of Hormuz open. Yet some aspects of the exercise highlighted the difficulties of conducting mine countermeasures (MCM) operations in the narrow strait. Future exercises should be more ambitious and involve greater international participation.


On July 1, as European Union sanctions went into force, Iran's parliamentary committee on national security and foreign policy proposed legislation to block the Strait of Hormuz in order to bar tankers carrying oil for countries that had imposed restrictions on the regime. On July 15, armed forces chief of staff Maj. Gen. Hassan Firouzabadi stated, "We have a contingency plan for the blockade of the strait," describing the scheme as "a viable plan." The Islamic Revolutionary Guard Corps naval commander, Rear Admiral Ali Fadavi, added, "The IRGC's naval forces have had the ability since the [Iran-Iraq] war to completely control the Strait of Hormuz and not allow even a single drop of oil to pass through." More recently, on September 17, IRGC commander Gen. Mohammad Jafari stated, "This is a declared policy by Iran that if war occurs in the region and the Islamic republic is involved, it is natural that the Strait of Hormuz as well as the energy [market] will face difficulties." To underline the point, Tehran matched IMCMEX with simultaneous naval mining exercises in the Caspian Sea.

Iran may not be able to close the strait, but it could employ a range of highly disruptive tactics to dissuade commercial tanker traffic and thus drive up oil prices. The regime is capable of attacking maritime traffic with antishipping missiles, artillery, airstrikes, submarines, fast-attack craft, and small boats, though laying mines is one of its most likely courses of action. In addition to a large arsenal of old moored mines (which could also be cut from their moorings and set adrift), it has more sophisticated MDM-6 moored mines and EM-52 bottom mines (which fire a rocket-propelled projectile upward from the seabed).

In addition, Iran could attempt undeclared mining of the strait as it did in the 1980s, using fishing dhows and commercial vessels to sow mines with a degree of plausible deniability. Although modern intelligence, surveillance, and reconnaissance capabilities make this a risky prospect, the IRGC may have adapted new clandestine tactics. Counterpiracy efforts in the Red Sea have shown that differentiating legitimate traffic from hostile actors remains difficult even in closely watched zones. Moreover, anchoring systems guided by global positioning systems and predictable currents could allow Iran to release mines far from their targets, widening the area in which its minelayers can operate.

From a strategic standpoint, Iran might opt for a protracted mining campaign that requires a costly, open-ended international effort to keep the strait open. In any scenario, vulnerable and slow-moving MCM vessels and helicopters would need to be very well protected during their missions, necessitating massive U.S. and allied naval and air cover. In addition to testing diplomatic and military resolve, such operations would be risky given the concentration of Iranian missile and attack boat capabilities within the confined strait.


For decades, the United States has systematically underresourced countermine warfare, preferring to leave this unglamorous mission to European partners in a division of labor left over from the Cold War. Accordingly, the U.S. military has long accepted its deficiency in dealing with the main naval threat in the Gulf: Iran's ability to surreptitiously lay mines in the Strait of Hormuz and around key Gulf Cooperation Council (GCC) anchorages. Whereas Britain's Royal Navy traditionally maintained four small but effective MCM vessels in the northern Gulf, U.S. Navy forces in Bahrain kept only two new minesweepers in service and two older vessels on standby. Experts agree that up to sixteen MCM vessels might be needed to keep Hormuz clear of mines.

Over the past year, mindful of growing tensions with Iran, the United States has taken a number of steps to reverse the dangerous shortfall of MCM capability in the Gulf:

  • More ships. The U.S. Navy's fiscal 2013 budget request included funds to send four newer MCM ships to the Gulf, doubling the U.S. countermine fleet there.
  • More helicopters. In June 2012, the Navy deployed four MH-53E Sea Dragon helicopters with mine-detecting sonar arrays to Bahrain.
  • Unmanned underwater vehicles. The mine-hunting SeaFox and MK18 Mod 2 Kingfish unmanned underwater vehicles have also been added to the MCM fleet. Their procurement was driven by U.S. Central Command head Gen. James Mattis, who called them an "urgent operational requirement." 
  • Command ship. The U.S. Fifth Fleet has established a new command in the Gulf focused entirely on mine warfare, overseen by Rear Admiral Kenneth Perry, vice commander of the Navy's mine and antisubmarine warfare efforts. The USS Ponce has been deployed as a mine warfare command ship.

Although the Navy spotlighted its new capabilities during IMCMEX, many aspects of the exercise seemed like missed opportunities. Maneuvers were conducted in parts of the Gulf, Arabian Sea, and Indian Ocean, but not the Strait of Hormuz, and the Fifth Fleet spokesman denied that they were aimed at Iran: "This exercise isn't about any nation or group. It's about being prepared in the event that some violent extremist group used mines." Moreover, only twenty-five ships took part, underlining the symbolic nature of the event for many of the participating nations. Only five countries -- the United States, Britain, France, Japan, and New Zealand -- advertised their involvement, while GCC nations kept their role quiet and reportedly sent observers rather than vessels.


Washington's increased focus on demining in the Gulf is significant and timely, but the recent reinforcements and exercises are only stopgaps. Some of the newly earmarked MCM forces are unlikely to be ready for deployment until 2014, including MK6 patrol boats, littoral combat ships, and new countermining helicopter systems. In the meantime, policymakers and military planners should take several steps to protect international trade and allied naval forces in the Gulf:

  • Recognize the potential for escalation. As Joint Chiefs chairman Adm. Mike Mullen noted on September 20, 2011, the lack of regular crisis communication channels with Iran has planted the "seeds for miscalculation," making it "virtually assured that we won't get it right" in a future crisis unless liaison relationships are established. Any plan to protect sea-lanes in the Strait of Hormuz must therefore recognize the high probability of escalation once naval forces are concentrated to protect MCM efforts. Losses to precious MCM assets are likely and should be accounted for during force planning.
  • Exercise in the strait. Although Hormuz is congested, sensitive, and certainly not the only part of the Gulf that Iran can target, there is some logic to holding an exercise aimed at clearing the strait in the strait. Doing so would send a powerful signal to Tehran.
  • Name and shame Iran. Despite political sensitivities, it makes no sense to be coy about the purpose of MCM exercises: Iran should be named as the potential adversary based on its repeated, explicit threats to the strait. U.S. war plans should also prioritize intelligence collection and information operations that can expose covert mining if Tehran goes that route.  
  • Stand up and be counted. Nations participating in MCM exercises should agree to be publicly identified, which would be a more powerful signal of solidarity.
  • Be creative. Iran's mine threat to oil tankers could also be reduced through novel means. For example, if a crisis erupts, old tankers could be sent to sweep the strait's inbound and outbound channels each morning in order to detonate any mines laid overnight. Double-hulled tankers are difficult enough to sink in normal circumstances and could serve as unsinkable mine-clearers if filled with buoyant materials. Alternatively, a consortium of nations could agree to temporarily assume the financial risk of any tanker transiting the strait.

Michael Knights is a Lafer fellow with The Washington Institute.