Iranian Warship Sunk in Indian Ocean After U.S. Submarine Torpedo Strike
Colombo, Sri Lanka – A U.S. Submarine sunk the Iranian frigate IRIS Dena in the Indian Ocean on March 4, 2026, approximately 40 nautical miles (74 km; 46 mi) south of Galle, Sri Lanka, resulting in the deaths of 87 sailors and the rescue of 32 others. The incident occurred as Washington and Israel intensified their bombardment of Iranian security forces, according to reports.
Details of the Sinking
Sri Lanka’s navy initiated a rescue mission after receiving a distress signal from the IRIS Dena, which had 180 people on board as reported by Sri Lanka’s Foreign Minister Vijitha Herath to Parliament. The frigate was struck by a U.S. MK 48 heavyweight torpedo according to the U.S. Naval Institute News. The United States Department of Defense has confirmed the attack as detailed on Wikipedia.
Firsts in Modern Naval Warfare
This event marks the first acknowledged wartime instance of a submarine sinking an enemy surface vessel since the sinking of ARA General Belgrano during the Falklands War and the first torpedoing of a ship by an American submarine since World War II according to Wikipedia. The IRIS Dena was a Moudge-class frigate commissioned in 2021.
Background and Context
The sinking of the IRIS Dena occurred amidst escalating tensions in the region, with the U.S. And Israel increasing their strikes against Iranian targets. Sri Lanka’s deputy foreign minister identified the warship as the frigate IRIS Dena, stating it was returning to Iran from an eastern Indian port as reported by Reuters. Approximately 61 sailors remain missing as of this report.
Key Takeaways
- A U.S. Submarine sunk the Iranian frigate IRIS Dena on March 4, 2026.
- 87 Iranian sailors were killed, and 32 were rescued.
- The incident occurred off the coast of Sri Lanka during a period of heightened regional conflict.
- This is the first acknowledged wartime sinking of a surface vessel by a submarine since the Falklands War.