In a major escalation of tensions in the Indian Ocean region, a submarine from the United States Navy launched a torpedo attack that sank an Iranian warship near the coast of Sri Lanka. The vessel targeted in the strike was the Iranian frigate IRIS Dena, which was operating in international waters south of the Sri Lankan city of Galle. According to defense officials, the attack marks the first time since World War II that a U.S. submarine has sunk an enemy warship using a torpedo in combat.

The strike reportedly occurred on March 4, 2026, when a U.S. fast-attack submarine fired a single Mark 48 torpedo at the Iranian frigate. The powerful torpedo struck the ship, causing catastrophic damage that quickly sent the vessel to the bottom of the sea. Military officials confirmed that the engagement was swift and highly precise, demonstrating the advanced targeting capabilities of modern submarine warfare.

The Iranian warship had approximately 180 crew members on board at the time of the incident. Reports indicate that at least 87 sailors were killed, while 32 survivors were rescued by Sri Lankan naval forces during search and rescue operations in the area. Several others were reported missing after the ship sank. The rescue effort involved ships from the Sri Lankan navy responding to distress signals sent shortly before the frigate disappeared from radar.

Defense officials stated that the Iranian frigate had recently participated in multinational naval activities in the region before the incident occurred. The sinking of the vessel represents a significant military event because submarine-launched torpedo attacks against warships have been extremely rare in modern conflicts. The last widely acknowledged case of a submarine sinking an enemy ship in combat was during the Falklands War, when an Argentine cruiser was destroyed by a British submarine. However, the 2026 incident is the first confirmed case involving a U.S. submarine since the end of World War II.

The event has also intensified concerns about the growing military confrontation involving Iran and the United States. Analysts believe the strike highlights the strategic importance of naval dominance in the Indian Ocean and the ability of submarines to operate undetected over long distances.

Experts note that modern submarines equipped with advanced sonar systems and high-precision torpedoes can engage targets silently and with devastating impact. The sinking of the IRIS Dena demonstrates how submarine warfare remains a powerful tool in modern naval conflicts despite technological advances in surface ship defenses.

As investigations and diplomatic reactions continue, the incident has drawn international attention and raised concerns about further escalation of military tensions in the region. Governments and defense analysts worldwide are closely monitoring the situation, as such events have the potential to influence global security dynamics and maritime stability in the Indian Ocean.