A United States submarine torpedoed and sank an Iranian warship in international waters off Sri Lanka’s southern coast on Wednesday, US Defense Secretary Pete Hegseth confirmed, in an incident that has heightened tensions in the Indian Ocean.

Sri Lankan authorities said several bodies had been recovered and 32 wounded sailors rescued. The injured were taken to a hospital in Galle for treatment. Officials were still working to account for nearly 150 other crew members, with search and rescue operations ongoing.

Sri Lanka’s Foreign Minister Vijitha Herath told parliament that around 180 personnel were on board the vessel, identified as IRIS Dena. The Moudge-class frigate sank about 40 nautical miles off Sri Lanka’s coast after issuing a distress call, officials said.

“A US submarine sank an Iranian warship off the southern coast of Sri Lanka,” Hegseth said, confirming American involvement hours after Sri Lankan authorities reported that an Iranian naval vessel had gone down at sea.

The circumstances leading to the strike were not immediately clear, and neither Washington nor Tehran provided further details on what prompted the confrontation in international waters.

The frigate had recently been active in regional naval engagements. A vessel named IRINS Dena was listed as a participant in a naval drill held in the Bay of Bengal from February 18 to February 25, according to the exercise website. It had also taken part in the International Fleet Review 2026 in India before beginning its return voyage.

Two weeks prior to the sinking, India’s Eastern Naval Command had welcomed the Iranian vessel during a port call at Visakhapatnam, part of routine naval diplomacy and engagement activities.

The sinking marks a rare direct military confrontation between US and Iranian forces in waters far from the Gulf, raising fresh concerns over maritime security and the potential for wider regional fallout.