An Iranian naval frigate, IRIS Dena, was reportedly sunk by a United States submarine in the Indian Ocean near the southern coast of Sri Lanka, marking a rare wartime torpedo strike and drawing attention to rising tensions in waters close to India’s strategic sphere.
The Iranian warship had recently participated in the Milan International Fleet Review hosted by the Indian Navy in Visakhapatnam from February 18 to 25 and was returning from India when it was targeted in international waters. Reports indicate that around 180 personnel were on board, with Sri Lankan authorities rescuing approximately 30 sailors, while many others remain missing.
Sri Lankan naval forces launched search and rescue operations near Galle, responding to a distress signal and spotting an oil slick at the site where the vessel reportedly sank. Survivors were transported to local hospitals for treatment as humanitarian assistance efforts continued.
Defence analysts note that the attack highlights the heavy presence of US naval assets in the Indian Ocean, particularly under the US Navy’s Fifth Fleet operations that span the Persian Gulf, Arabian Sea and surrounding maritime regions. Nuclear-powered attack submarines operating in the region are capable of launching torpedo strikes designed to break a ship’s keel, often leaving little trace of the vessel.
The incident is strategically significant for India as it occurred close to its maritime neighbourhood, though outside India’s territorial waters. Experts say the strike illustrates how the ongoing US–Iran conflict has expanded into the Indian Ocean region, raising concerns about regional stability and maritime security.
Some analysts have pointed out that while the attack took place in India’s strategic backyard, it occurred in international waters, likely avoiding direct diplomatic complications for New Delhi. However, the development has sparked debate over the implications for India’s strategic environment, particularly given its ties with both the United States and Iran.
The sinking of IRIS Dena is also notable for its rarity. Only a handful of warships have been sunk by submarines since World War II, making this one of the most significant naval incidents in recent decades.
The event comes amid a wider escalation in the Middle East conflict involving Iran, the United States and Israel, with growing concerns that the instability could spill over into the Indian Ocean and South Asian region.
