On March 4, 2026, U.S. Defense Secretary Pete Hegseth announced that a U.S. submarine had torpedoed an Iranian warship, the IRIS Dena, off the southern coast of Sri Lanka.
The Sri Lankan navy rescued 32 survivors from the crew of 180, according to The Associated Press, and recovered 87 bodies.
Following the attack, social media users claimed the Dena was unarmed, that it was participating in a multination naval exercise in India that the U.S. backed out of at the last minute and that after torpedoing the ship, the U.S. Navy broke with international maritime law and refused to rescue survivors.
Snopes readers wrote in looking for clarity.
After reviewing the evidence, we found that some elements of the claim were relatively accurate, while others were harder to verify because of a lack of information.
We contacted representatives from the Pentagon, Iran's foreign ministry, India's defense ministry and the Sri Lankan government. None had responded to our inquiries at time of publication; we will update this report if they do.
From Feb. 15-25, 2026, representatives from 74 nations gathered in Visakhapatnam, India, to participate in the International Fleet Review and MILAN 2026 naval exercises. According to the event website, the Iranian navy sent the Dena to participate. A Feb. 25 U.S. Navy news release said one of its P-8A Poseidon planes also participated.
According to several sources that cover naval news and India, the U.S. originally planned to send the USS Pinckney, a guided-missile destroyer, to the exercise. A news release from the Navy showed the Pinckney departed Singapore on Feb. 4. It did not participate in MILAN 2026, however.
It is also worth noting that the U.S. submarine — not the Pinckney — did not torpedo the Dena while it was participating in the naval exercise — the ship was on its way back to Iran when the U.S. sank it.
The claim that the Dena was unarmed depends on how one classifies whether a ship is unarmed.
As a warship with mounted guns, it is impossible for the Dena to be "unarmed" in the most basic sense. However, firing said weapons is possible only if the Dena has ammunition on board.
According to the BBC, which spoke with an Indian strategic affairs expert, visiting ships at multinational naval exercises like the Dena "usually do not carry a full combat load of live munitions unless scheduled for a live-fire drill."
There were some live-fire exercises during MILAN 2026, but it was unclear whether the Dena participated. Even if it had, according to the BBC, "ships carry only tightly controlled ammunition limited to the specific exercises."
The claim that the ship was unarmed (i.e., was not carrying ammunition) may have originated from an X post made by Kanwal Sibal, India's former foreign secretary. In our request for comment to the Indian defense ministry, Snopes asked whether Sibal's claim was true.
Finally, the claim the U.S. broke international law by refusing to pick up survivors would be difficult to determine without the U.S. government making such an admission.
According to international maritime law, all ships, civilian and military, are obligated to help a ship in distress but are not required to put themselves in danger while helping. Sri Lanka is responsible for search and rescue in the area where the Dena sank, according to a U.S. Coast Guard map. In our questions to all parties, we asked about their activities in the area on the day of the attack, and whether they had other ships in the area that could have assisted in saving the Iranian sailors.
The Associated Press reported that following the torpedoing, a separate Iranian ship, the IRIS Bushehr, requested assistance while in Sri Lankan waters. The Sri Lankan government took custody of the vessel after discussing with the ship's captain and Iranian officials. The U.S. pressured Sri Lanka to not repatriate the Iranian sailors, according to Reuters.