Iranian military forces loaded naval mines onto vessels in the Persian Gulf last month, signaling preparations to potentially block the Strait of Hormuz following Israel's June 13 strikes on targets inside Iran, according to two U.S. officials familiar with classified intelligence.
The preparations, previously unreported and detected by U.S. intelligence assets, raised alarms in Washington over the prospect that Tehran was readying to shut down one of the world's most critical maritime chokepoints for global energy shipments. The Strait of Hormuz, a narrow waterway between Oman and Iran, sees approximately 20% of global oil and gas transit, and any disruption would reverberate through global markets.
Iran has not deployed the mines, the officials said, and the intention behind the loading remains unclear. Tehran may have sought to bluff the United States or signal seriousness without actual intent to follow through. "The Iranians could have prepared the mines to convince Washington that Tehran was serious about closing the strait, but without intending to do so," one of the officials said, according to REUTERS.
The action took place after Israel's initial missile barrage and shortly before the United States conducted coordinated airstrikes on three Iranian nuclear facilities on June 22. Following the U.S. strikes, Iran's parliament backed a proposal to close the strait, although the move was symbolic and non-binding. Tehran's Supreme National Security Council retains the authority to implement such a decision.
"Thanks to the President's brilliant execution of Operation Midnight Hammer, successful campaign against the Houthis, and maximum pressure campaign, the Strait of Hormuz remains open, freedom of navigation has been restored, and Iran has been significantly weakened," a White House official stated.
Iran's ability to block the strait has long been a strategic lever, even though the Islamic Republic also relies on the channel to export its own crude oil. The U.S. Defense Intelligence Agency estimated in 2019 that Iran possessed more than 5,000 naval mines, many of which can be rapidly deployed via small high-speed vessels.
U.S. naval assets in the region, particularly the Bahrain-based Fifth Fleet, are tasked with ensuring maritime security. Prior to the U.S. airstrikes, American mine countermeasure ships were temporarily removed from Bahrain to mitigate risk of Iranian retaliation. These ships, typically four in number, are being phased out in favor of littoral combat ships equipped with anti-mine systems.
At its narrowest, the Strait of Hormuz spans just 21 miles, with designated shipping lanes only 2 miles wide in each direction. It serves as the vital export route for crude oil from key producers including Saudi Arabia, the United Arab Emirates, Iraq, and Kuwait. Qatar, the world's largest liquefied natural gas exporter, also depends on the strait for LNG shipments.
