US special forces spent four months conducting a secret mine-clearing mission in the Strait of Hormuz in an attempt to open up the waterway, the Financial Times reported Sunday.
Iran has said it placed mines in international and Omani waters following the outbreak of the war. The International Maritime Organization estimated in June that roughly 80 mines had been deployed along important shipping routes.
The covert operation was carried out amid ongoing exchanges of strikes between the US and Iran in and around the Strait, according to people familiar with the mission.
Navy SEAL divers worked with unmanned vessels, robots, and specialized underwater equipment to locate and remove suspected Iranian mines, often operating at night.
The objective of the operation was to make the strait safer for commercial vessels that had largely avoided the waterway since the US and Israel attacked Iran in February.
US President Donald Trump announced last week that “all mines” in the strait's international waters had been removed or destroyed, a claim subsequently confirmed by the US military.
The announcement came despite reports showing that three US vessels normally assigned to mine-countermeasure operations in the Gulf had been operating in the Indian and Pacific oceans since at least early June.
US uses divers, unmanned systems to clear mines
Mine-clearing can be painstaking, lengthy, and inherently dangerous in peacetime, and an active conflict adds further risks.
For these operations, small teams of Navy divers worked from inflatable-hulled boats, supported by unmanned surface vessels and submersibles equipped with advanced sonar to locate underwater objects. Despite the advanced technology, divers may still have had to approach and destroy the mines directly.
“That is usually followed up by a navy diver who’s got to get in the water and approach the mine, and then put a charge on it and destroy it,” retired US Navy captain Bill Hamblet told the FT.
No US casualties have been reported in connection with the operation.
“It is an extremely time-consuming process,” said Nitya Labh, an associate fellow at Chatham House. “They are doing, essentially, active bomb detonation underwater.”
Questions remain over whether Strait is mine-free
Despite Trump's declaration, uncertainty remains over whether the entire Strait of Hormuz has been cleared.
Shipping companies and maritime security advisers believe areas near Oman, where the US has been directing ships through the strait, have likely been cleared, but remain less certain about the rest of the waterway.
“It doesn’t take much to put a mine back in because there is a lot of small-boat traffic going across Hormuz every night," a tanker industry executive said.
The uncertainty itself gives Tehran leverage. Even the possibility of mines can discourage commercial shipping and increase insurance costs, while concerns remain that Iran could deploy new mines in areas already cleared by US forces.
Oil prices dropped five percent following Trump's announcement but have since returned to their previous levels as strikes have resumed.
“It’s hard to know what to believe,” said Ethan Connell, assistant director of Taiwan Security Monitor and a mine warfare expert. “Iran is certainly trying to re-mine.”
Hamblet said Iran benefits strategically from the perception that it can disrupt the critical waterway.
“The Iranians have realized that their strongest card is the perception that they control the Strait of Hormuz. If they can convince the world that they can threaten the strait, that’s their strongest source of strategic leverage,” he said.