Search and rescue operations were launched by the Indian Navy after a distress signal from the Iranian naval frigate IRIS Dena, which sank in the Indian Ocean near Sri Lanka following a torpedo strike attributed to a United States submarine.Officials said the distress call from the warship reached the Maritime Rescue Coordination Centre in Colombo during the early hours of March 4. The vessel had been operating roughly 20 nautical miles west of Galle, within the search-and-rescue region overseen by Sri Lankan authorities. Upon receiving the alert, the Indian Navy deployed aircraft and ships to assist rescue efforts already underway in coordination with Sri Lankan agencies.
According to naval officials, a long-range maritime patrol aircraft was dispatched at around 1000 hours on March 4 to support the ongoing operation. Another aircraft equipped with air-droppable life rafts remained on standby to provide immediate assistance if survivors were located in the water. Naval vessels operating in the region were also diverted toward the search area as part of the humanitarian response.
The frigate had been returning to Iran after taking part in multinational naval activities hosted off the eastern coast of the subcontinent. Defence analysts say the vessel had participated in the International Fleet Review and Exercise Milan, a large maritime gathering that brought together naval forces from multiple countries for drills and cooperative security exercises.
The attack occurred in international waters off the southern coast of Sri Lanka, marking a significant escalation of naval hostilities tied to the broader confrontation involving Iran and a coalition aligned with Washington and its partners. Military officials in Washington later confirmed that a United States Navy submarine fired a Mark 48 torpedo that struck the Iranian vessel.
Reports from Sri Lankan authorities indicate that about 180 personnel were on board the frigate at the time of the explosion. Rescue teams from the Sri Lanka Navy and Air Force reached the area soon after the distress call was received and managed to recover survivors from the water. Dozens of sailors were brought to medical facilities in Galle for treatment after suffering injuries and exhaustion.
Casualty figures have varied as rescue and recovery operations continue. Sri Lankan officials have confirmed that multiple bodies were retrieved from the sea while several crew members remain unaccounted for. The scale of the losses has added urgency to the multinational effort to locate survivors and recover those missing.
India’s involvement has centred on humanitarian assistance rather than combat operations. Naval spokespersons emphasised that assets were deployed solely to support search and rescue efforts under international maritime conventions governing assistance to ships in distress. The presence of Indian aircraft and ships has also helped expand the area under surveillance during the operation.
INS Tarangini, a sail training vessel that was operating nearby, was directed to the search zone and reached the area during the afternoon of March 4. Another vessel, INS Ikshak, sailed from Kochi to reinforce the effort and remained in the region to continue scanning the waters for survivors or debris linked to the incident.
The sinking has drawn attention because it represents one of the most consequential naval engagements involving a submarine in decades. Military historians note that submarines have rarely been used to destroy surface warships in open combat since the late twentieth century, making the strike a notable development in modern naval warfare.
Strategic analysts have also pointed to the geographical significance of the incident. The waters off Sri Lanka lie close to some of the busiest maritime trade routes connecting the Middle East with East Asia. An armed encounter involving major powers in this area underscores how far the confrontation linked to the Iran conflict has extended beyond the Persian Gulf.
Regional governments have reacted cautiously as details of the incident continue to emerge. Sri Lankan authorities reiterated their neutrality and emphasised their responsibility to coordinate humanitarian rescue operations within their designated maritime zone. The focus of local agencies has remained on locating missing sailors and assisting survivors brought ashore for medical treatment.
Iranian officials have condemned the strike and demanded accountability, describing the destroyed vessel as a legitimate naval asset operating in international waters. Diplomatic reactions from several countries have called for restraint as tensions surrounding the wider conflict continue to rise.