‘Thought it was safe in international waters’: US submarine strike near Sri Lanka sinks Iranian warship returning from Indian naval event
A United States submarine sank an Iranian warship off the southern coast of Sri Lanka, US Defence Secretary Pete Hegseth said on Wednesday. In a Pentagon briefing, Hegseth said the strike on the warship was the first such attack on an enemy since World War II.
“An American submarine sunk an Iranian warship that thought it was safe in international waters,” Hegseth said. “Instead, it was sunk by a torpedo.”
Sri Lankan Foreign Minister Vijitha Herath had earlier told parliament that 180 people were on board the Iranian vessel, identified as the IRIS Dena, while deputy foreign minister told reporters that at least 80 people were killed.
Sri Lankan navy spokesman Commander Buddhika Sampath said 32 people had been rescued by the Sri Lankan navy and were being treated in hospital in the southern port city of Galle.
The sinking occurred amid a rapidly escalating conflict involving the United States, Israel and Iran. Military strikes launched by the United States and Israel on February 28 killed Iran’s Supreme Leader, Ayatollah Ali Khamenei, along with several senior officials of the country’s regime.
Early-morning distress call
The IRIS Dena, a Moudge-class frigate belonging to the Iranian Navy’s Southern Fleet, issued a distress call around 5.30 am local time while operating roughly 40 nautical miles off the coastal city of Galle, Sri Lankan defence officials told The Indian Express. Rescue operations by Sri Lanka’s navy and air force were underway throughout the morning.
The warship had participated in the International Fleet Review (IFR) and multilateral exercise, MILAN-2026, organised by the Indian Navy last month.
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The US Navy destroyer USS Pinckney, which was also scheduled to take part in the IFR and MILAN, did not participate due to emergent requirements. A US P-8 aircraft had participated in the exercises.
Indian Defence sources said the incident falls within Sri Lanka’s assigned area of operation. “Any other Navy can only get involved if they seek assistance for the operation,” a source said.
Many of the 32 sailors rescued from the frigate were in a critical condition because of severe injuries and prolonged time in the water, according to two senior Sri Lankan government officials who spoke on condition of anonymity.
The wounded were transported to Karapitiya Teaching Hospital in Galle, the region’s largest medical facility, where emergency wards were placed on alert to receive casualties.
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“We estimate that the frigate had approximately 180 sailors aboard at the time of the incident. Most crew members were still unaccounted for as of Wednesday afternoon,” said a top government official in Colombo.
Foreign Minister Herath confirmed in parliament that Sri Lanka had launched a rescue mission and said the ship sank just outside Sri Lanka’s territorial waters but within the country’s designated search-and-rescue zone.
“We responded to the distress call under our international obligations,” Navy spokesman Sampath told the media. Two naval ships and a surveillance aircraft were dispatched to assist with the rescue.
A Sri Lankan official added, “The US Navy Ohio-class submarines routinely patrol the Indian Ocean from the American military base on Diego Garcia (a strategic island facility used for operations across the Middle East and Asia). We are examining sightings and maritime tracking data.”
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Returning from India
Iranian naval deployments in the region have been relatively rare. The IRIS Dena had been participating in diplomatic naval activities in the weeks leading up to the incident. In February, the frigate attended the IFR in the Indian port city of Visakhapatnam, where it docked alongside ships from multiple countries. The Indian Navy had extended a warm welcome to the frigate as it arrived in Visakhapatnam in the third week of February.
This was highlighted by Congress’s Pawan Khera, who posted on X, “Today, an Iranian naval vessel – returning from the Milan 2026 International Fleet Review, where it had been invited by India – was sunk by a US submarine at the edge of Indian waters near Sri Lanka. Does India have no influence left in its own neighbourhood? Or has that space also been quietly ceded to Washington and Tel Aviv?”
The frigate, named after Mount Dena in southwestern Iran, is a domestically built warship designed for patrol and combat missions in regional waters. It displaces roughly 1,300 to 1,500 tons and carries a range of anti-ship missiles, naval guns and torpedo launchers. The ship also includes a helicopter landing pad and radar systems capable of tracking multiple targets.
A military analyst based in Chennai said the vessel would have been heavily armed, carrying Qader anti-ship missiles, a 76-millimetre naval gun and torpedo systems, among other weapons. Sri Lankan authorities said they were withholding video footage of the rescue operation because it involved the military assets of another country.
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Sri Lanka has maintained a policy of neutrality in international conflicts, but occupies a strategically significant location along major shipping routes in the Indian Ocean.
The waters south of Sri Lanka lie near some of the world’s busiest maritime corridors linking Asia, the Middle East and Europe. Naval vessels from multiple countries, including the United States, China and India, regularly transit or patrol the region.
With more than half the crew still missing, officials warned that the final toll could rise significantly in the coming days.
– With AP and Reuters
