U.S. Submarine Sinks Iranian Warship, Escalating Tensions in Indian Ocean

A U.S. Submarine sank the Iranian warship IRIS Dena in the Indian Ocean off the coast of Sri Lanka on Wednesday, March 4, 2026, marking the first U.S. Sinking of an enemy ship by torpedo since World War II. The incident has dramatically escalated tensions in the region and prompted a search and rescue operation led by Sri Lanka.

Details of the Sinking

According to the Sri Lankan Navy, 87 bodies have been recovered, and 32 people were rescued following the sinking of the IRIS Dena. U.S. Defense Secretary Pete Hegseth confirmed the attack, stating the Iranian vessel was sunk by a torpedo fired from an American submarine as reported by the Associated Press. The IRIS Dena issued a distress call at dawn before being sunk.

U.S. Response and Broader Context

Hegseth described the attack as a “quiet death” and emphasized its historical significance, noting it was the first such sinking by the U.S. Since World War II as detailed by The Times of Israel. The U.S. Military reported destroying 17 Iranian vessels, with a stated goal of sinking the entire Iranian navy. The Israel Defense Forces indicated the American military had assumed full responsibility for targeting Iran’s maritime activities.

The IRIS Dena

The IRIS Dena was described as a heavily armed frigate, equipped with heavy guns, surface-to-air missiles, anti-ship missiles, and torpedoes, and capable of carrying a helicopter according to reports. It was considered Iran’s “prize ship” as stated by the AP.

Sri Lanka’s Role

Sri Lanka’s Foreign Minister Vijitha Herath confirmed the rescue of 32 critically wounded sailors from the IRIS Dena, which sank just outside Sri Lankan territorial waters The Times of Israel reported. The nation has been actively involved in the search and rescue operation.

Escalation of Conflict

The sinking of the IRIS Dena occurred as Washington and Israel intensified bombardment of Iranian security forces and other symbols of power according to the Associated Press, signaling a significant escalation in the ongoing conflict.

Iran International similarly confirmed the U.S. Strike and the subsequent search and rescue operation.