Thousands of US ground troops are reportedly heading to the Middle East, raising speculation that they will be assigned to occupy Iran’s Kharg Island, a key fuel hub in the northern Persian Gulf that is responsible for 90% of Iran’s oil exports.
But Kharg is just one of dozens of Iranian islands in the Gulf, and other islands may be more important to ensuring safe passage of ships and naval vessels through the Strait of Hormuz.
Seven of these islands – Abu Musa, Greater Tunbu, Lesser Tunbu, Hengham, Qeshm, Larak, and Hormuz – form what researchers at Sun Yat-sen University in Zhuhai, China, call Iran’s “arch defense.”
In a 2022 paper for the Canadian Center for Science Education, Iran researcher Enayatollah Yazdani and China researcher Ma Yanzhe said of the Strait of Hormuz, “A hypothetical curve connecting these islands could further help us understand Iran’s strategic advantage in controlling security.”
Abu Musa, the smallest of the seven and the westernmost part of the arch, the Great Tunnel and the Small Tunnel, are key to controlling the strait, the two researchers wrote.
According to the researchers, the limited distance between the three islands and the almost shallow depth of the bay “force large warships and tankers to pass through them on foot.” This could make them easy targets for Islamic Revolutionary Guards Corps (IRGC) fast attack ships, mine layers, and drones operating from these islands.
Yazdani and Maher wrote that Iranian officials refer to Iran and other Gulf islands as Tehran’s “unsinkable aircraft carrier.”
The Revolutionary Guards announced last year that it was strengthening its presence in Abu Musa, Greater Tunbu, and Lesser Tunbu, according to a report by the Foundation for Defense of Democracies.
“According to our tactical approach, this archipelago must be armed and operational. We have the capability to attack enemy bases, warships and assets in the region,” Rear Admiral Alireza Tansiri, commander of the Revolutionary Guards Navy, said at the time. (Tansiri was killed in an Israeli operation, Israel and U.S. Central Command announced Thursday.)
Because the island is unsinkable, an attempted landing on Kharg would require the removal of Iranian military positions on the island to allow U.S. warships (and possibly ships transporting U.S. Marine Expeditionary Units (MEUs)) safe passage into the heart of the Persian Gulf.
Carl Schuster, a Hawaii-based analyst and former director of the U.S. Pacific Command Joint Information Center, said the islands are “strategically located to have control” over ships attempting to enter and leave the bay.
There are no plans for U.S. amphibious attacks on Iranian islands.
US President Donald Trump on Thursday announced a 10-day extension to the deadline to begin attacks on Iran’s energy infrastructure, to April 6, to see if an agreement can be reached with Tehran to end the hostilities. An earlier deadline was set to expire Friday night ET.
US Secretary of State Marco Rubio told reporters that “progress has been made” in negotiations with Iran.
However, a suspension of overall military operations was not announced. Defense Secretary Pete Hegseth said Thursday that the U.S. will continue to “negotiate the bomb.”
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CNN reported that two MEU units, approximately 4,000 troops, are heading to the Middle East. Additionally, approximately 1,000 soldiers from the U.S. Army’s 82nd Airborne Division have been alerted to deploy.
Schuster said the full strength of these forces could be needed to seize important islands for Iran’s defense. “We will use two MEUs to ensure overwhelming force,” he told CNN.
The US military will be stationed on the island either by air or by sea.
U.S. Navy ships carry landing craft, such as LCACs (Landing Crafts with Air Cushions), which can slide up to shore to disembark troops and their equipment. But getting them into the Gulf could be problematic, as mother ships would have to slip past Iranian defenses that may be on mainland Iranian islands early in the curve, such as Hormuz, Larak, Qeshm, and Hengham.
CNN military analyst Cedric Layton said Thursday that it is located at the eastern entrance to the Larac Strait, creating a problem for naval vessels trying to enter the bay.
If Raraku were to launch missiles or small attack craft, “[Iran]could cut off everything that passes through the strait. This is an important military objective,” he told CNN’s Erin Burnett.
Along with helicopters, Navy ships also carry CV-22 Osprey tilt-rotor planes capable of vertical takeoff and landing. However, these aircraft are slow-moving and vulnerable to air defenses that may have failed in previous air strikes.
Troops from the 82nd Airborne could parachute onto the island from high-flying aircraft, but such attacks would require less equipment than can be transported by sea.
Overall, the attack on the islands could take anywhere from two days to two weeks to complete, but if successful, Schuster said, it would yield significant results.
“By installing radar and military forces, we can monitor activity in the strait without giving Iran a staging area for drones or anything like that,” Schuster said of Abu Musa.
A March 24 report from the Institute for the Study of War said that U.S. and/or Israeli warplanes began attacking Iranian military infrastructure, including aircraft hangars, ports, and warehouses in Abu Musa, Greater Tunb, and Lesser Tunb. Schuster said such an attack would occur before an amphibious invasion.
But capturing the islands is only part of the mission. Schuster said an occupation force of about 1,800 to 2,000 people would be needed to ensure the islands were not used again by the Iranians.
And that could leave occupying U.S. forces vulnerable.
“Seizing these territories would also require U.S. forces to thwart drone, missile, and artillery attacks from mainland Iran, potentially drawing the U.S. into a prolonged and unpopular engagement on Iranian territory and potentially increasing U.S. casualties,” said a new report from the New York-based nonpartisan Soufan Center analysis organization.
Schuster said drone and missile defense are essential for the U.S. military stationed on three Iranian islands.
“If[Iran]has access to drones and ballistic missiles, it will attack hostile forces on those islands,” he said.
Deep sea diving of Kharg Island after US attack
But Schuster believes it would be more advantageous to try to capture the three islands in the lower Gulf, rather than Kharg, the oil center in the upper Gulf.
“There is little risk of any negative impact on the Iranian government’s economy in the future,” he said.
Much of Iran’s oil passes through the Khalg, so damage to oil infrastructure in the fighting could set back post-war reconstruction years.
Earlier this month, Iran attacked a liquefied natural gas facility in Qatar, causing damage that could take up to five years to repair, Qatar Energy officials said.
But analysts said the U.S. action to occupy Abu Musa and Greater and Lesser Tunbu could have repercussions after the war.
In 1971, when the United Arab Emirates gained independence from colonial Britain, Iran, then ruled by the US-backed Shah, took control of the islands.
Since then, the UAE has challenged Tehran’s actions as illegal at the United Nations and offered to negotiate a resolution to the dispute.
Iran claims historical and geographical rights to these islands. The UAE has said it may take the dispute to the International Court of Justice if the issue cannot be resolved.
The UAE embassy in Washington said in a statement that the United States and other countries support the UAE’s claims.
And that’s where the U.S. occupation of the islands will be difficult, Schuster said, calling it a “political dilemma” for allies the UAE and the United States.
If the United States returns the island to Iran’s new government, it risks angering the UAE, Schuster said. But he added that if the US returns them to the UAE, it could undermine the legitimacy of Iran’s new regime.
Of course, that only matters if the United States succeeds in retaining the captured islands at the end of the conflict. But Schuster said this is a type of conflict that has the potential for new flare-ups of fighting, so planners need to consider it.
“This is why modern military planning is so complex,” he says.
“Every choice has a negative impact. There is no perfect plan or solution. There is only a balance of costs, risks, and impacts, both intended and unintended.”
