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U.S. strike sinks IRIS Dena
A U.S. submarine fired a torpedo that struck and sank the Iranian frigate IRIS Dena in international waters off southern Sri Lanka, an action confirmed publicly by U.S. officials and described as a rare submarine sinking.
“A U.S. submarine sank an Iranian warship in international waters of the Indian Ocean near Sri Lanka, widening the U.S. and Israel’s conflict with Iran, NPR reports.”
Multiple outlets report the attack took place roughly 40 nautical miles south of Galle as the warship was returning from regional naval events, and U.S. and Pentagon statements circulated footage of the strike that officials called a "quiet death."
The sinking has been framed by U.S. leaders as a direct strike on Iranian maritime capabilities amid a wider campaign.
Sea rescue and casualties
Sri Lankan search-and-rescue teams reached the scene after a dawn distress call and recovered survivors, bodies and life rafts.
Authorities and media reported widely varying casualty figures, including roughly 32 survivors taken to a Galle hospital and body counts reported as 80–87 recovered, with scores still unaccounted for amid conflicting tallies.
Sri Lankan officials said they found oil patches and no intact wreck visible at the distress location.
Context of naval strike
U.S. officials put the strike in the context of a broader, coordinated campaign to degrade Iran’s maritime forces.
“Defense Secretary Pete Hegseth confirmed that a U.S. submarine fired a Mark 48 torpedo that sank the Iranian frigate IRIS Dena on March 3–4, 2026, as part of a five-day U.S.–Israeli operation called Operation Epic Fury that destroyed 17 Iranian vessels.”
Pentagon and CENTCOM spokespeople and some outlets described it as part of "Operation Epic Fury" or an extended U.S.–Israeli effort that has struck many Iranian vessels.
Defense Secretary Pete Hegseth and other U.S. briefers emphasized the precision and strategic aim of the action, naming the Dena a high-value target and, in some accounts, describing the torpedo as a Mk-48 heavyweight.
At the same time, officials and analysts noted questions about how the ship was tracked and engaged without apparent detection.
Indian Ocean maritime escalation
The sinking has sharply heightened regional tensions and prompted international concern about escalation and maritime security in the Indian Ocean and beyond.
Media and officials described the event as an extraordinary extension of the U.S.–Israeli campaign beyond the Middle East.
Reports link it to dozens of other strikes on Iranian naval assets and say it risks disrupting shipping lanes, prompting evacuations and complicating diplomacy.
Several outlets noted accompanying strikes and interceptions across the region, and governments and commentators warned the action could widen the conflict.
Disputed strike accounts
Questions about verification, legality and conflicting accounts remain prominent.
“Critics and some former U.S. officials questioned the legality and necessity of the strike, saying the Iris Dena was not reported to be engaged in hostilities and a former Pentagon civilian‑harm chief called the attack illegal.”
Critics and some former U.S. officials questioned the necessity and lawfulness of the strike.
Media flagged sourcing and factual inconsistencies.
Sri Lanka emphasized its search-and-rescue role and said no other ships or aircraft were seen at the scene.
Several reports urged independent corroboration of specific details, especially casualty totals, the precise weapon used and the full operational justification.
Governments called for investigations and restraint to avoid further escalation.