US Strike On Iranian Warship In Indian Ocean Leaves 87 Dead

According to available information, a total of 180 people were on board the Iranian vessel at the time of the attack.

The Pentagon has stated that one of the primary objectives of the US-Israeli war against Iran, launched on Saturday, is to eliminate Iran’s navy.

Source : X/@IN_HQENC

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Key points generated by AI, verified by newsroom

• US submarine sank Iranian warship IRIS Dena in Indian Ocean.
• Vessel recently participated in Indian naval exercise MILAN 2026.
• US confirmed strike, released video; 80 fatalities reported.

At least 87 people were killed after a US submarine sank an Iranian warship in the Indian Ocean, Reuters reported on Wednesday. The vessel, IRIS Dena, had taken part in a naval exercise in India just weeks earlier.

Citing the Sri Lankan Navy, the Associated Press reported that 87 bodies were recovered and that 32 people were rescued following sinking of the warship IRIS Dena.

IRIS Dena, a Moudge-class frigate, had earlier visited India in 2024 to participate in the multilateral naval exercise MILAN. It was also part of the 2026 edition of the same exercise and had set sail for home when it was attacked by the US submarine.

#WATCH | The US military releases the visuals of the attack on an Iranian warship in the Indian Ocean.

(Visual Source: Department of War) https://t.co/a5JmdAOUEh pic.twitter.com/IqcqtkhMP6

— ANI (@ANI) March 4, 2026

In a statement issued on February 16, the Indian Navy described MILAN 2026 as one of the largest multilateral naval exercises in the Indo-Pacific, bringing together navies from across the world to enhance interoperability, maritime domain awareness and collective response capabilities.

The harbour and sea phases of the drill focused on complex maritime operations, including anti-submarine warfare, air defence, and search and rescue.

US Confirms Strike, Releases Video

While Washington has not confirmed the number of fatalities, US Defence Secretary Pete Hegseth acknowledged the submarine strike and presented it as a demonstration of America’s global reach in its war on 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.

The US Department of War released black-and-white footage showing what appeared to be a submarine periscope view followed by an explosion in the distance. The release of near real-time visuals of a submarine strike is unprecedented and reflects changes in how modern conflicts are fought and communicated.

Reports suggest the Iranian warship likely did not detect the US submarine, even at periscope depth, underscoring the capabilities of American submarine tactics.

Questions Over Surveillance

It remains unclear whether the US submarine had been tailing or monitoring IRIS Dena during its voyage to and from India for MILAN 2026. Defence analysts have theorised that the submarine may have tracked the Iranian vessel throughout its journey. Passive tracking of foreign naval assets for intelligence purposes is a common practice among major navies.

Rescue Efforts And Missing Crew

Sri Lankan authorities said 32 crew members from IRIS Dena had been rescued, while 148 sailors remain missing, with hopes fading of finding more survivors.

Hegseth described the strike as a “quiet death” and said it marked the first time since World War II that the US had sunk an enemy ship by torpedo. "Like in that war," he said, "we are fighting to win."

The Pentagon has stated that one of the primary objectives of the US-Israeli war against Iran, launched on Saturday, is to eliminate Iran’s navy.