Sri Lanka recovered dozens of bodies after the ship went down in the Indian Ocean.
COLOMBO, SRI LANKA — A U.S. Navy submarine fired a torpedo that sank an Iranian warship in the Indian Ocean near Sri Lanka, U.S. and Sri Lankan officials said Wednesday, in an attack the Pentagon described as the first time since World War II that an American submarine has sunk an enemy vessel.
The strike pushed a widening U.S.-Iran confrontation far beyond the Persian Gulf and forced Sri Lanka into a major search-and-rescue effort along a busy shipping corridor. Sri Lankan authorities said they recovered 87 bodies and pulled 32 survivors from the water, while dozens more were still unaccounted for. U.S. Defense Secretary Pete Hegseth confirmed the attack and said it was carried out by a fast-attack submarine using a single torpedo.
The warship, identified by Sri Lankan officials as the IRIS Dena, went down late Tuesday, March 3, after Sri Lanka’s navy received a distress signal off the island’s southern coastline near Galle. Sri Lanka’s navy said it reached the area to find debris and survivors in the water. Hegseth, speaking at the Pentagon on Wednesday, March 4, said the ship was in international waters and that the U.S. submarine attack was deliberate. He described the strike as a “quiet death,” and the Defense Department released video it said was recorded through a submarine periscope as the target was struck and sank.
Gen. Dan Caine, chairman of the Joint Chiefs of Staff, said the submarine fired a Mark 48 torpedo and that the weapon had “immediate effect.” In the Pentagon video, the Iranian ship appears to suffer a violent underwater blast that tears through the hull before the vessel disappears beneath the surface. Sri Lankan officials said the ship had about 180 people aboard, and that some of the rescued crew members were taken to hospitals. One survivor was in critical condition, Sri Lanka’s navy said, and search teams were still trying to account for those missing as daylight search flights widened the grid offshore.
Iran did not immediately release a full casualty list, but survivors who reached Sri Lankan rescuers described a sudden strike consistent with a submarine attack, according to officials involved in the rescue. Sri Lanka’s government said its response was humanitarian and focused on saving lives, while noting that the sinking happened outside Sri Lanka’s territorial waters. The incident quickly became a new flash point in a conflict that U.S. and Israeli officials say has intensified in recent days, with Tehran responding to airstrikes and other attacks by launching missiles and drones at targets across the region.
The IRIS Dena is viewed as a prominent Iranian naval vessel, and its loss carried both military and political weight for Tehran. Officials said the ship was heavily armed and capable of operating far from Iran’s coastline, a type of platform Iran has used to signal reach in the Indian Ocean and beyond. Reuters reported the vessel was returning to Iran after taking part in the Indian-hosted “Milan” naval exercise in the Bay of Bengal, an event that draws ships from many countries for drills meant to promote cooperation. The timing added to the shock in the region, where commercial shipping and naval traffic already have been on edge as fighting has spread.
In Washington, the Pentagon framed the torpedo attack as a rare modern use of submarine-on-ship firepower and as a warning to Iranian forces operating outside the Gulf. Hegseth said the ship “thought it was safe in international waters,” but he did not identify the U.S. submarine involved. U.S. officials also did not say how the Iranian ship was selected as a target, what intelligence supported the decision, or whether U.S. commanders believed the vessel posed an immediate threat. Those questions matter because the ship was far from the main areas where U.S., Israeli and Iranian forces have traded fire in recent days.
Military historians note U.S. submarines have fired torpedoes in combat since World War II, but almost always at submerged targets or in limited postwar incidents that did not include confirmed sinkings of enemy warships by torpedo. ABC News cited the Pentagon as saying the last U.S. submarine torpedo sinkings of enemy vessels occurred in August 1945, during the final days of World War II. The Pentagon’s emphasis on the “first since World War II” label highlighted how unusual it is for major powers to use submarines in open warfare at sea, even as undersea fleets have remained central to deterrence and intelligence for decades.
For Sri Lanka, the emergency unfolded quickly and close to shore. Navy boats and aircraft were sent toward the distress call, and rescuers described a wide field of floating wreckage, life vests and oil sheen on the water. Fishermen along the southern coast reported seeing helicopters and patrol craft moving out from harbor areas, while local officials prepared hospitals to receive injured sailors. Sri Lanka’s navy said 32 people were rescued, but the number of missing remained uncertain because it was not clear how many crew members made it into the water and how many were trapped on the ship as it sank.
The discovery of dozens of bodies raised concerns about how long survivors had been exposed before help arrived, and about the possibility that additional victims could drift with currents away from the initial search area. Sri Lankan officials said they were coordinating with other agencies and monitoring the coastline for debris. International maritime routes run close to Sri Lanka, and the incident drew immediate attention from shipping companies and regional navies watching for spillover effects. The sinking also raised the risk of miscalculation as navies operate in the same waters, sometimes without clear communication during a fast-changing crisis.
Iran’s broader warnings suggested it could respond in ways that extend beyond naval action. In comments reported by the Associated Press, Iranian officials vowed major retaliation and signaled the war could expand further, even as the country faces internal turmoil and leadership uncertainty. U.S. and Israeli officials said their strikes have targeted Iranian military sites and other symbols of power, while Iran has launched missiles and drones toward multiple locations in the region. The new attack site in the Indian Ocean added another geography to a conflict already disrupting energy markets and shipping through key chokepoints.
Diplomatic channels also appeared strained. Sri Lanka, which seeks to avoid being drawn into big-power disputes, emphasized that it was responding to an emergency at sea and that the strike itself occurred beyond its jurisdiction. Still, the presence of dead and wounded sailors on Sri Lankan soil created pressure for answers about what happened and what comes next. Analysts said Colombo could face requests from Iran for help with repatriation, inquiries about evidence recovered during rescue work, and demands for assurances about the treatment of survivors.
U.S. officials did not announce new legal steps tied to the sinking, but they indicated military operations would continue. The Pentagon did not say whether more undersea strikes were planned, and it offered no timeline for releasing additional details about the submarine’s mission. Sri Lankan authorities said they would continue searching offshore through the next weather window and would update casualty and survivor totals as information was confirmed. Iranian officials were expected to address the sinking publicly and could seek an emergency diplomatic response, though no international hearing date or formal inquiry had been announced by Wednesday afternoon.
As night fell in southern Sri Lanka, the search boats kept running grids over dark water, with spotlights scanning for life rafts or floating lights. Local residents along the coast watched the sea lanes in silence, and hospital staff prepared for the possibility of more survivors brought in by helicopter. The survivors already recovered were described as exhausted and injured, with some suffering from shock and exposure. Sri Lankan officials said the rescue operation would remain focused on saving lives, even as the incident drew global attention and raised fears of further clashes on the high seas.
By Wednesday, March 4, Sri Lanka said 87 bodies had been recovered and 32 people rescued, with dozens still missing as search teams worked offshore near Galle. U.S. officials said the Iranian ship was sunk by a single torpedo in international waters, and further briefings were expected as the conflict’s next moves became clearer.
Author note: Last updated March 4, 2026.