Maritime Executive: Iranian Frigate Torpedoed and Sunk off Sri Lanka, At Least 83 Dead

On Wednesday, Defense Secretary Pete Hegseth told reporters that a U.S. Navy submarine had torpedoed and sunk the Iranian frigate IRIS Dena in international waters of the Indian Ocean, confirming the speculation attending the vessel’s sinking off Sri Lanka on Tuesday night. It was the first time that an American sub used a torpedo to sink an enemy ship in combat since the Second World War, and the first time for any submarine since 1982, when the Royal Navy attack sub HMS Conqueror sank the Argentine cruiser ARA General Belgrano off the Falklands. 

Video released by the Pentagon showed a heavy torpedo detonating under the IRIS Dena’s stern, lifting the vessel into the air and breaking its keel. The warship sank before rescuers could arrive on scene, leaving only an oil slick, floating debris, and 32 survivors behind. 

“It was sunk by a torpedo, a quiet death – the first sinking of an enemy ship by a torpedo since world war II,” said Hegseth. “Like in that war, back when we were still the war department, we are fighting to win.”

83 bodies have been recovered from the scene so far, according to Sri Lankan deputy defense minister Aruna Jayasekara. 32 survivors were delivered to the national hospital in Galle for treatment. In total, about 180 Iranian sailors are believed to have been on board for the voyage.

U.S. forces have been systematically sinking Iranian warships in the Middle East as part of hostilities with Tehran, and Joint Chiefs chairman Gen. Dan Caine claimed Wednesday that more than 20 ships have been hit to date. U.S. Central Command has pledged to continue the strikes until Iran’s navy is gone. The attack on IRIS Dena is unique by virtue of location: Galle is thousands of miles away from the conflict zone, and located in the Indo-Pacific Command area of responsibility.

IRIS Dena was one of Iran’s most modern combatants. Commissioned in 2021, the vessel had indigenously-built engines and armaments. It gained publicity in 2022-3 for its participation in a round-the-world tour; it was dispatched to India for the International Fleet Review 2026 exercises, and had just wrapped up that event before its sinking.