US Submarine Sinks Iranian Frigate: Iran Warns of Retaliation | Sri Lanka Conflict

Second Iranian Warship Approaches Sri Lanka Amidst Escalating Tensions

A second Iranian warship is reportedly approaching Sri Lankan territorial waters, just one day after a United States Navy submarine sank the Iranian frigate IRIS Dena in the Indian Ocean. The sinking, which occurred approximately 40 nautical miles off the coast of Galle, Sri Lanka, resulted in the confirmed deaths of at least 87 Iranian sailors, with 32 rescued and 61 still missing as of Thursday, March 5, 2026. This incident marks a significant escalation in the ongoing 2026 Iran war and raises concerns about further maritime conflict in the region.

Sri Lankan Media Minister Nalinda Jayatissa informed parliament that the second Iranian vessel is currently positioned just outside Sri Lankan waters, though specific details regarding its course and intent remain limited. Authorities are preparing to handle the remains of the 87 sailors who perished in the attack on the IRIS Dena, with arrangements being made in Galle. The 32 rescued sailors are receiving medical treatment under heightened security at a local hospital.

The Sinking of IRIS Dena: A First Since World War II

The destruction of the IRIS Dena represents the first instance since World War II where a U.S. Submarine has successfully sunk an enemy warship using a torpedo. According to reports, the attack was carried out using a Mark 48 torpedo as part of “Operation Epic Fury,” a broader American military campaign aimed at diminishing Iran’s naval capabilities. Footage released by the U.S. Department of War showed the torpedo striking the stern of the IRIS Dena, causing it to rise partially out of the water before sinking.

The Iranian vessel had recently participated in naval exercises in India and was returning when it was targeted. Iran’s foreign minister has warned of repercussions for the U.S. Action, stating the ship was a guest of the Indian Navy.

Escalation of Conflict and Regional Implications

The sinking of the IRIS Dena is occurring against a backdrop of wider conflict. Iran’s Revolutionary Guards announced on Thursday that they had struck a U.S. Tanker in the Persian Gulf and the vessel is currently reported to be on fire. This retaliatory action underscores the escalating tensions and the potential for further clashes in the region.

The conflict is also impacting global shipping routes. The potential for Iran to disrupt traffic through the Strait of Hormuz, a critical chokepoint for global oil and gas supplies, is a major concern. Shipping through the strait has already significantly decreased, leading to a surge in energy prices, with Brent crude rising 12% and European natural gas benchmarks up approximately 50% this week. Experts suggest that even the threat of Iranian interference could be enough to disrupt global energy markets. Defence Security Asia reports that the strike signals a dramatic escalation in Indian Ocean naval warfare.

Sri Lanka’s Position and Ongoing Search Efforts

Sri Lanka has maintained a neutral stance throughout the conflict and continues to urge dialogue as a means of resolving the situation. Sri Lankan Navy vessels are actively involved in search and rescue operations, attempting to locate any remaining survivors from the IRIS Dena. Traces of oil spills have been detected, further complicating the rescue efforts. The Sri Lanka Navy responded to a distress call from the vessel but did not find it at the initial location. Naval News details the initial response and ongoing search operations.

Details of the IRIS Dena and Operation Epic Fury

The IRIS Dena was a Moudge-class frigate equipped with various armaments, including Qader anti-ship missiles, Sayyad air-defense missiles, and a 76 mm main gun. The vessel’s primary role was power projection. “Operation Epic Fury,” under which the attack was conducted, is focused on dismantling Iran’s maritime combat capabilities. The operation has raised concerns about the potential for a wider regional conflict and the impact on global shipping security. The U.S. Secretary of War, Pete Hegeseth, confirmed the sinking of the IRIS Dena.

This incident marks a significant turning point in the 2026 Iran war, demonstrating a willingness by the United States to engage in direct naval confrontation. The arrival of a second Iranian warship near Sri Lanka underscores the heightened tensions and the potential for further escalation in the coming days. The situation remains fluid, and the international community is closely monitoring developments in the region.

In this handout image, an Arleigh Burke-class guided-missile destroyer USS Thomas Hudner (DDG 116) fires a Tomahawk land attack missile in support of Operation Epic Fury.