US Submarine Sinks Iranian Warship, Triggering Sharp Warnings from Tehran

A US submarine has sunk an Iranian warship in the Indian Ocean, an attack that Iran’s Foreign Minister warns the US will “bitterly regret.”

US Secretary of Defense Pete Hegseth confirmed on Wednesday that an American submarine fired a torpedo at an Iranian vessel, resulting in its sinking.

Hegseth described the event as a “quiet death” for the ship, which he said “thought it was safe in international waters.” He also claimed this marked “the first sinking of an enemy ship by a torpedo since World War Two” .

The Target: IRIS Dena

The destroyed vessel is the IRIS Dena, a Iranian frigate. According to Sri Lankan officials, the ship went down approximately 40 kilometers (25 miles) off the country’s southern coastline .

The Sri Lankan Navy responded to a distress call on Wednesday morning. They immediately launched a major rescue operation.

However, the scene facing rescuers was dire. They found no ship. Instead, they saw only oil patches. Life rafts also floated on the water.

So far, rescuers have recovered at least 80 bodies. They have also rescued 32 survivors. Consequently, these survivors are receiving treatment for serious injuries. They are currently at a hospital in the port city of Galle.

Furthermore, based on the ship’s documentation, officials believe approximately 180 personnel were aboard at the time of the attack.

A “Guest” Returning from Naval Exercises

The sinking has added a diplomatic dimension to the conflict, as the IRIS Dena was returning from a friendly visit to India.

The ship had recently participated in the International Fleet Review 2026 and Exercise Milan, a multinational military event hosted by the Indian Navy in Visakhapatnam .

Iran’s Foreign Minister, Abbas Araghchi, emphasized this point in a strong condemnation on social media.

“The US has perpetrated an atrocity at sea, 2,000 miles away from Iran’s shores,”

Araghchi posted on X.

“Frigate Dena, a guest of India’s Navy carrying almost 130 sailors, was struck in international waters without warning. Mark my words: The US will come to bitterly regret the precedent it has set” .

A Widening Conflict

This naval engagement occurred as the broader conflict between US-led forces and Iran entered its fifth day. The US and Israel have been conducting air strikes on Iranian targets, and Iran has launched retaliatory missile attacks .

The US military has released video footage showing the moment a torpedo struck the ship, causing its stern to rise before exploding. Consequently, US officials have framed the attack as a demonstration of military reach.

Gen. Dan Caine, Chairman of the Joint Chiefs of Staff, stated the operation showcased America’s ability to “hunt, find, and kill an out-of-area deployer” on a global scale .

Sri Lanka, which has remained neutral in the conflict, continues its search and rescue operations, bound by international obligations to save lives at sea