--- title: "U.S. Navy Submarine Torpedoes Iranian Frigate In Indian Ocean" description: "This is the first sinking of an enemy ship by a U.S. submarine since World War II." date: "2026-03-04" modified: "2026-03-04" authors: - name: "Howard Altman" job_title: "Senior Staff Writer" link: "https://www.twz.com/authors/howard-altman" - name: "Joseph Trevithick" job_title: "Deputy Editor" link: "https://www.twz.com/authors/joseph-trevithick" url: "https://www.twz.com/news-features/u-s-submarine-sinks-iranian-warship-in-the-indian-ocean" categories: - "Around The Globe" - "Iran" - "Iranian Navy" - "Middle East" - "Navies" - "News & Features" - "Sea" - "Submarines" --- # U.S. Navy Submarine Torpedoes Iranian Frigate In Indian Ocean ![]() *US Military* A U.S. Navy attack submarine has sunk an Iranian warship in the Indian Ocean, the Pentagon has confirmed. Authorities in Sri Lanka had earlier announced they had rescued Iranian sailors from the [*Moudge* class frigate]() IRIS *Dena* after what they said appeared to be a submarine attack. This is the first known attack by an American submarine on a surface warship since World War II and the first such action anywhere since the *Churchill* class HMS *Conqueror* sank the Argentine Navy cruiser ARA *General Belgrano* during [the Falklands War]() in 1982. "Yesterday in the Indian Ocean, ... an American submarine sunk an Iranian warship that thought it was safe in international waters," Secretary Pete Hegseth said at a press conference this morning. "Instead, sunk by a torpedo, quiet death, the first sinking of an enemy ship by a torpedo since World War II." ![]() *A view of the Iranian frigate, bow up, sinking after being torpedoed by a US Navy submarine in the Indian Ocean. *US Military** At the same briefing, Chairman of the Joint Chiefs of Staff U.S. Air Force Gen. Dan “Razin” Caine said the same attack had been carried out by an unspecified "fast attack submarine" using a single [Mk 48 torpedo](). Authorities in Sri Lanka [had earlier announced]() they had rescued Iranian sailors from the IRIS *Dena* after what they said appeared to be a submarine attack. The Sri Lanka Navy responded to a distress call from the ship, and launched rescue operations at 6:00 AM local time, Sri Lanka's foreign minister told ​parliament. ![]() *A stock picture of the Iranian Navy frigate IRIS *Dena*. (Indian Navy)* "What ​we know at this point is that 79 people were ​rescued and brought to the hospital and one of them was seriously injured. ‌Another ⁠101 are believed to be missing and the vessel has sunk," a Sri Lanka Navy source [told *Reuters*](). A ​Sri Lanka Navy spokesman also said that “32 people ⁠injured in the incident had been rescued by \[the\] Sri Lankan ​navy and were under treatment in hospital,” *Reuters* explained, adding that one of those brought in had subsequently died. Iran's [*Moudge* class frigates](), derived from the earlier *Alvand* class, are among Iran's most modern and capable surface combatants. Iranian *Alvand* class warships and derivatives thereof [have also been targeted in port]() in U.S. strikes in the course of Operation Epic Fury. ![]() *Another stock picture of the IRNS *Dena*. (Indian Navy)* "We've destroyed more than 20 Iranian naval vessels, including – in addition to the frigate outside of the area," Gen. Caine also said this morning. "\[We've\] effectively neutralized, at this point in time, Iran's major naval presence in theater." "Over the next 24 to 48 hours, CENTCOM \[U.S. Central Command\] will continue to strike infrastructure and naval capability, and we'll continue to assess our progress against the military objectives," he added. U.S. officials have previously highlighted the total destruction of Iran's Navy as a central objective of Operation Epic Fury, an effort that is now extending beyond the Middle East. ***UPDATE: 9:32 AM EST –*** The Pentagon has now released a video, seen below, of the torpedo attack on the Iranian frigate in the Indian Ocean, as seen through the periscope (technically [an optronics or photonics mast]()) on the U.S. Navy submarine. The infrared footage shows a massive detonation at the stern end of the ship. https://twitter.com/DeptofWar/status/2029193757162139762?s=20 Modern heavyweight anti-ship torpedoes like the Mk 48 are designed to cause maximum damage after striking the target ship well below the waterline. The Mk 48 torpedo's [roughly 650-pound warhead]() is powerful enough to 'lift' a warship and cause its hull to buckle, if not break entirely, as is regularly [seen in U.S. Navy sinking exercises](). You can read more about how modern submarines execute torpedo attacks, which are nothing like how they are depicted in movies and television, in a past TWZ feature [here](). Contact the author: howard@thewarzone.com ## Author Howard is a Senior Staff Writer for *TWZ*. He writes frequently about conflict, focusing heavily on the Middle East and Ukraine, and interviews with military and intelligence officials and industry leaders from around the globe. He lives near Tampa, Florida, home of U.S. Central Command, U.S. Special Operations Command. ### Author social links [Twitter]() [LinkedIn]()