An unnamed U.S. Navy submarine has sunk the Iranian warship IRIS Dena with a torpedo in international waters off the southern coast of Sri Lanka as part of Operation Epic Fury.
United States Secretary of Defence Pete Hegseth did not name the frigate during today’s (Wednesday’s) Pentagon briefing, but earlier the Sri Lankan Navy had reported that the IRIS Dena had sunk in the Indian Ocean.
Reports have confirmed at least 80 lives lost, with 32 sailors so far picked up by a Sri Lankan search-and-rescue operation. Though described as a destroyer by Iran, the Moudge-class Dena was more usually described as a frigate.
The 95m warship had been launched in 2015; she was thought to have a crew of about 140 and to have carried anti-ship and anti-air missiles fired via a vertical launch system (VLS). With her demise she became the first ship sunk by a US submarine in active combat since World War II.
During the same briefing Defence Secretary Hegseth also identified another of the Iranian Navy vessels which have been sunk as IRIS Shahid Soleimani, the lead ship of an Iranian class of missile corvettes.
He said: “The Iranian Navy rests at the bottom of the Persian Gulf: combat ineffective, decimated, destroyed, defeated… pick your adjective. In fact last night we sank their prize ship, the Soleimani.
“Yesterday, in the Indian Ocean… an American submarine sunk an Iranian warship that thought it was safe in international waters… instead it was sunk by a torpedo.”
The Pentagon has just released footage of the attack on the Dena, apparently recorded from the submarine’s periscope.
https://t.co/J4grAgoqxc pic.twitter.com/szOofLkh9W
— Department of War 🇺🇸 (@DeptofWar) March 4, 2026
- You can check the latest Operation Epic Fury updates online via CENTOM’s X account and you can watch the Defence Secretary’s full briefing on the U.S. Department of War website