New Delhi: At least 87 people were killed after a United States submarine sank an Iranian naval vessel in the Indian Ocean, according to reports citing Sri Lankan authorities, in one of the most dramatic naval developments in the ongoing conflict involving Iran.
The vessel, identified as IRIS Dena, a Moudge-class frigate of the Iranian Navy, had recently participated in the multinational naval exercise MILAN 2026 in India before heading back towards Iranian waters when it was reportedly struck by a torpedo launched from a US submarine.
While the United States has not officially confirmed the casualty figures, US Defence Secretary Pete Hegseth acknowledged that an American submarine had carried out the strike on the Iranian warship. Speaking to reporters, he said the attack demonstrated the reach and capabilities of the US military amid the ongoing conflict with Iran.
The Pentagon also released black-and-white footage showing what appeared to be a submarine periscope view followed by an explosion at sea. Analysts noted that the public release of near real-time visuals of a submarine strike is rare and reflects changing approaches to information dissemination during modern conflicts.
According to officials in Sri Lanka, rescue teams recovered 87 bodies after the warship sank off the country’s coast, while dozens of sailors were rescued. Search operations were continuing for several crew members who remain missing.
“The Sri Lanka Navy and the Sri Lanka Air force engaged in rescue operations as per the International Convention on Maritime Search and Rescue for which Sri Lanka has signed way back in 1979,” Sri Lankan Minister of Foreign Affairs Vijitha Hearth was quoted as saying by the Daily Mirror.
IRIS Dena had previously taken part in the MILAN naval exercise hosted by India, one of the largest multilateral maritime drills in the Indo-Pacific region. The exercise brings together navies from across the world to strengthen interoperability, maritime domain awareness and cooperation in complex maritime operations.
Defence experts suggested that the US submarine may have been monitoring the Iranian vessel during or after its participation in the exercise, as it is common for navies to track foreign warships for intelligence purposes during international deployments.
The sinking marks a significant escalation in maritime hostilities linked to the broader US-Israel conflict with Iran. US officials have indicated that weakening Iran’s naval capabilities forms part of the military objectives of the ongoing campaign.
