The Pentagon has confirmed that a United States submarine torpedoed and sank an Iranian warship in the Indian Ocean, marking a significant escalation in the ongoing US-Israeli conflict with Iran.

Defence Secretary Pete Hegseth announced the strike on Wednesday, describing it as a demonstration of America's global naval reach. He stated that the frigate IRIS Dena believed itself safe in international waters but was swiftly despatched by a torpedo.

This represents the first time a US submarine has sunk an enemy vessel by torpedo since the Second World War, according to Hegseth, who characterised the operation as a "quiet death".

The IRIS Dena had been spotted recently in the Bay of Bengal during India's International Fleet Review in Visakhapatnam on 18 February 2026, underscoring its active deployment in regional waters.

Sri Lankan authorities responded promptly to the frigate's distress call, issued at dawn on Wednesday. Rescue operations commenced within an hour, approximately 40 kilometres south of the southern port of Galle.

The Sri Lankan Navy recovered 32 crew members from the sunken vessel. Tragically, 148 other sailors remain missing, with officials expressing low hopes for further survivors.

By the time rescue boats arrived, the frigate had completely submerged, leaving only an oil slick on the surface as evidence of its demise.

Sri Lanka's Foreign Minister Vijitha Herath informed parliament that the rescued Iranians were rushed to a major hospital in the island's south. Two navy vessels and an aircraft were mobilised for ongoing search efforts.

A Sri Lankan defence official noted to AFP that searches continue, though the fate of the remaining crew is uncertain. Navy spokesman Buddhika Sampath confirmed the discovery of a few bodies in the vicinity.

Sampath emphasised that Sri Lanka's response aligns with its international maritime obligations, as the incident occurred within the nation's designated search-and-rescue zone in the Indian Ocean.

Sri Lanka has maintained a neutral stance amid the Middle East conflict, repeatedly calling for dialogue to de-escalate tensions. The country relies heavily on remittances from over a million nationals employed in the region, vital for its economic recovery following the 2022 crisis.

Neither the Sri Lankan Navy nor Air Force released footage of the operation, citing sensitivities involving a foreign military.

Police enhanced security around the Galle hospital as injured Iranian sailors arrived under naval escort.

Iran's Ambassador to Colombo, Alireza Delkhosh, was unavailable for immediate comment on the sinking.

The Pentagon framed the attack as part of broader objectives in the US-Israeli campaign against Iran, launched on Saturday, aimed at neutralising the Islamic Republic's naval capabilities.

Hegseth drew parallels to the Second World War, declaring that the US is "fighting to win" in this confrontation.

The incident highlights the expanding theatre of operations into the Indian Ocean, raising concerns over regional stability and international shipping lanes.

AFP