With thousands of US ground troops reportedly on the way to the Middle East, speculation is mounting that they may be assigned to take Iran’s Kharg Island, a key fuel hub in the northern Persian Gulf which handles 90% of Tehran’s oil exports.
But Kharg is just one of dozens of Iranian islands in the gulf, and others may be more important to securing the safe passage of ships – and naval vessels – through the Strait of Hormuz.
Seven of these islands – Abu Musa, Greater Tunb, Lesser Tunb, Hengam, Qeshm, Larak and Hormuz – form what researchers at Sun Yat-sen University in Zhuhai, China, call Iran’s “arch defense.”
“A hypothetical curve connecting these islands would further help to understand Iran’s strategic superiority in controlling the security” of the Hormuz strait, Iranian researcher Enayatollah Yazdani and Chinese researcher Ma Yanzhe wrote in a 2022 paper for the Canadian Center of Science and Education.
Abu Musa, Greater Tunb and Lesser Tunb – the smallest of the seven and at the western end of the arch – are key to strait control, the two researchers wrote.
Because of the limited distance between them and the depth of the water in the largely shallow gulf, “large warships and tankers are forced to walk past” the three islands, the researchers said. That can make them easy targets for Islamic Revolutionary Guard Corps (IRGC) fast-attack boats, mine layers, or drones operating from those islands.
Iranian officials have referred to them and other gulf islands as Tehran’s “stationary and unsinkable aircraft carriers,” Yazdani and Ma wrote.
Last year, the IRGC said it was reinforcing its presence on Abu Musa, Greater Tunb and Lesser Tunb, according to a report from the Foundation for Defense of Democracies.
“Our tactical approach dictates that we must arm and operationalize this group of islands. We have the capability to strike enemy bases, warships, and assets in the region,” IRGC navy commander Rear Adm. Alireza Tangsiri said at the time. (Tangsiri has now been killed in an Israeli operation, Israel and US Central Command said Thursday.)
Because the islands are unsinkable, Iranian military positions on them would have to be eliminated to ensure the safe passage of US warships – potentially those carrying US Marine Expeditionary Units (MEUs) – into the heart of the Persian Gulf, if a landing were to be attempted on Kharg Island.
The islands are “strategically located to control any shipping” trying to leave or enter the gulf, said Hawaii-based analyst Carl Schuster, a former director of the US Pacific Command’s Joint Intelligence Center.
There is no timeline for possible US amphibious assaults on any of Iran’s islands.
US President Donald Trump said Thursday he was extending a deadline for initiating strikes on Iran’s energy infrastructure for 10 days to April 6, to see if a deal could be reached with Tehran to end the fighting. An earlier deadline was set to expire Friday evening, Eastern time.
US Secretary of State Marco Rubio told reporters “progress has been made” in the negotiations with Iran.
But no pause was announced in the overall military campaign. Defense Secretary Pete Hegseth said Thursday the US would continue “negotiating with bombs.”