To prevent recent airline and shipping incidents from escalating into a wider military confrontation with Iran, all sides will need to exercise great caution in the Persian Gulf and the skies over Yemen.
On April 28, Saudi-led coalition aircraft bombed runways at Yemen's al-Rahaba Airport to prevent an Iranian Airbus A310 plane from landing there. The Sana airport is currently controlled by Houthi/Zaidi forces with close ties to Shiite Iran, and the plane belonged to Mahan Air, a company affiliated with Iran's Islamic Revolutionary Guard Corps. At the controls was a famously reckless ex-IRGC cargo pilot who had stubbornly ignored orders from Saudi F-15 crews to change course, spurring the runway strikes that rendered the airport inoperable and eventually forced him to turn back.
Iranian officials, especially within the IRGC, are frustrated by the coalition's actions against Houthi/Zaidi militias and by their own inability to provide military assistance to them. Only days before the airport incident, IRGC commander Maj. Gen. Mohammad Ali Jafari had called for a more aggressive stance against coalition operations in Yemen, while Hassan Firouzabadi, the chairman of the General Armed Forces Staff, called for "heavy-handed punishment" of the Saudis. Just last week, a convoy of cargo ships from Iran had attempted to run the Saudi blockade and deliver supplies and possibly arms to Yemeni ports under Zaidi control. The convoy was reportedly escorted by two of the IRGC Navy's Tondar-class missile boats (armed with Ghader anti-ship missiles, whose range is up to 200 miles), but it was called back after the U.S. Navy sent the aircraft carrier USS Theodore Roosevelt and the guided missile cruiser USS Normandy from the Persian Gulf. The standoff was brief and politically courteous, but it also carried a clear message for Iran.
The same day as the aerial showdown over Sana, in what may or may not be a coincidence, a swarm of IRGCN gunboats confronted the MV Maersk Tigris, a Marshall Islands-flagged container ship traveling from the Saudi port of Jeddah to the United Arab Emirates. They ordered the ship to change course for the Iranian port of Bandar Abbas; when the captain initially refused, they fired shots across his bow and boarded the ship. U.S. Naval Forces Central Command (NAVCENT) responded by dispatching the destroyer USS Farragut and various aircraft to monitor the situation, but the container ship was already well inside Iranian waters by that point. Under its 1983 Compact of Free Association with the Marshall Islands, the United States is responsible for defending the republic and any vessels bearing its flag.
Although several Iranian sources framed the seizure as a legal issue with the vessel's operating company, the action seems more like a clear warning to the Saudi-led coalition that the Yemen blockade will not be tolerated without retaliation. In that sense, the incident is yet another episode in the region-wide rivalry between Tehran and Riyadh.
Recent progress in the nuclear negotiations has led some to hope that the Islamic Republic will become more responsible and responsive on the regional stage. Yet by removing the near-term threat of military action against Iran's nuclear facilities, a deal could instead embolden Tehran to adopt a more aggressive regional posture in the coming years -- perhaps even rolling back to the pre-1996 era, when Iran and its proxies operated more actively against U.S. interests in the Middle East, culminating in the Khobar Towers bombing against American troops in Saudi Arabia. In fact, Supreme Leader Ali Khamenei already ruled out any linkage between a nuclear deal and Iranian support for Shiite militant groups during his high-profile April 9 speech. And in March, General Jafari went so far as to threaten "any enemy who makes a strategic mistake against the Islamic revolutionary regime" with "total annihilation," even calling for the overthrow of the Saudi monarchy.
In recent years, the IRGC has tightened its grip on the Strait of Hormuz and the Persian Gulf entrance channels by creating a Fifth Naval District out of Bandar Lengeh. This district encompasses a stretch of water just inside the Gulf between Qeshm and Kish islands, including the three disputed islands of Abu Musa and the Greater and Lesser Tunbs as well as Sirri island. While the navigation channels through the Strait of Hormuz itself fall entirely within Omani waters, the channels and separation zones immediately inside the Gulf run through Iran's territorial waters, overseen by IRGC surveillance posts and marine units on Abu Musa, the Tunbs, Sirri, Hengam, and Qeshm.
Three years ago, the IRGCN revised its military doctrine and adopted a punitive coercive strategic approach that includes so-called "smart control" of traffic through the thirty-mile-wide strait. Under this strategy, the IRGC could deny passage to ships from countries that impose sanctions on Iran or confront its regional interests militarily, and such measures could quickly escalate into a wider military confrontation with Gulf Arab countries and the United States. In the case of the Maersk Tigris, the ship was confronted at the approach to the strait, which could mean it was seized in haste in Omani or international waters -- a potentially worrisome sign for regional stability. Even if the incident proves to be a relatively minor one with limited consequences, the fact remains that Iran has multiple means of causing major disruptions to Gulf shipping should the Yemen confrontation get out of hand, including thousands of sea mines, shore-based missile and artillery batteries, heavily armed speedboats, and midget submarines. The United States could be caught unwillingly in a fight between old regional foes, so it must be prepared if the Gulf's unpredictable nature once again shows its colors.
Caution should also be exercised in the skies over Yemen. If Saudi-led coalition actions result in the loss of an Iranian airliner, the Islamic Republic would undoubtedly use it as a propaganda coup -- and as pretext for a range of measures leading to further destabilization.