87 Killed as US Submarine Sinks Iranian Warship Returning From India Naval Exercise
At least 87 sailors were killed after a United States submarine torpedoed and sank an Iranian naval warship in the Indian Ocean, news agency AFP reported on Thursday, citing Sri Lankan naval officials involved in rescue operations.
The vessel, IRIS Dena, a Moudge-class frigate of the Iranian Navy, sank off the coast of Sri Lanka, where authorities have launched an extensive search and rescue operation. Officials said dozens remain missing while several survivors have been rescued from the sea.
According to Sri Lankan Navy officials, 87 bodies have been recovered so far, while 32 survivors have been brought ashore. Authorities said 61 sailors are still missing, and search teams continue to comb the waters near the site where the frigate sank.
The warship had recently participated in MILAN 2026, a large multinational naval exercise hosted by India, and had departed the region when the attack reportedly took place.
US Defence Secretary Pete Hegseth confirmed the submarine strike, describing it as a demonstration of American military capability during the ongoing conflict with Iran.
“An American submarine sunk an Iranian warship that thought it was safe in international waters. Instead, it was sunk by a torpedo,” Hegseth told reporters.
He described the attack as a “quiet death”, adding that it marked the first time since World War II that the United States Navy had sunk an enemy vessel using a torpedo fired from a submarine.
The US Department of Defense also released black-and-white footage believed to be from a submarine periscope, showing what appears to be a distant explosion at sea. Analysts say the release of such near real-time visuals of a submarine attack is extremely rare and reflects changing dynamics in modern warfare and military information sharing.
Military analysts believe the Iranian frigate likely did not detect the US submarine before the torpedo strike, suggesting the attacking vessel may have been operating undetected at periscope depth.
The IRIS Dena had earlier taken part in the MILAN naval exercise, one of the largest multilateral naval drills in the Indo-Pacific region. According to the Indian Navy, the exercise aims to enhance interoperability, maritime domain awareness, and collective response capabilities among participating countries.
The exercise includes both harbour and sea phases, focusing on complex maritime operations such as anti-submarine warfare, air defence drills, and search-and-rescue coordination.
Defence analysts say it remains unclear whether the US submarine had been tracking the Iranian warship since it departed Iran for the naval exercise in India, although such surveillance operations are common among major naval powers for intelligence gathering.
The Pentagon said the attack was part of the broader US-Israeli war against Iran, which officials say aims in part to weaken or eliminate Iran’s naval capabilities.
Meanwhile, search operations led by Sri Lankan naval authorities are continuing as rescuers attempt to locate missing sailors and recover additional victims from the waters where the frigate sank. [KNT]
