US Confirms Its Submarine Sank Iranian Warship Off Sri Lanka Coast

US Defence Secretary Pete Hegseth said that the US sank an Iranian warship near Sri Lanka with a torpedo on Wednesday. Earlier in the day, the Sri Lankan navy reported that the IRIS Dena sank in the Indian Ocean. Almost 150 went missing, and several sailors died after the frigate sank.

"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.

Calling the attack "quiet death", he said that the strike was the first of its kind on an enemy since World War II.

.@SECWAR “In the Indian Ocean—an American submarine sunk an Iranian warship, that thought it was safe in international waters.

Instead, it was sunk by a torpedo—Quiet Death.

The first sinking of an enemy ship by a torpedo since World War 2. Like in that war—back when we were… pic.twitter.com/Y97YQBxQza

— DOW Rapid Response (@DOWResponse) March 4, 2026

The Pentagon says one of the main aims of the US-Israeli war against Iran, launched Saturday, is to wipe out the country's navy. 

A spokesman said that the Sri Lankan navy has recovered "a few bodies" of Iranian sailors after what crew members reported as an explosion.

"We have found a few bodies from the area where the ship had gone down," local navy spokesman Buddhika Sampath told reporters in Colombo, adding that the search for others was continuing.

The IRIS Dena is a Moudge-class frigate, which was returning to Iran after participating in the MILAN 2026 multinational naval exercises in Visakhapatnam.

Foreign Minister Vijitha Herath told Parliament that Sri Lanka's navy received information that the ship IRIS Dena, with 180 onboard, was under distress, and that the island nation sent ships and air force planes on a rescue mission.

An Israeli military official said that top US and Israeli commanders began to plan the opening strike of the war on Iran three weeks ago. He said that after the Israeli government decided to attack Iran, the top military brass reached out to the Pentagon to coordinate the cooperation.