An Iranian Navy frigate sank off Sri Lanka's southern coast early Wednesday after a suspected submarine attack, leaving at least 101 crew members missing and dozens injured, according to sources in the island nation's defense establishment.

The IRIS Dena, a Moudge-class warship commissioned in 2021 and one of Iran's most advanced surface combatants, issued a distress call at dawn from a position about 25 to 40 kilometers south of Galle in international waters. Sri Lanka's Navy and Air Force launched a search-and-rescue operation, rescuing between 30 and 79 sailors, many critically wounded, and transporting them to a hospital in Galle. Several bodies were also recovered from the sea.

The frigate carried approximately 180 crew members and had recently participated in the International Fleet Review 2026 exercises in Visakhapatnam, India, before heading back. Defense sources told local media the vessel was struck by a foreign submarine, but Sri Lankan military spokesmen rejected claims of a confirmed attack, stating the cause remained under investigation and no other vessels or aircraft were observed in the area.

Foreign Minister Vijitha Herath confirmed the sinking during a parliamentary session, noting the rescue of 32 critically injured sailors and emphasizing Sri Lanka's commitment to maritime obligations. Navy spokesman Buddhika Sampath said operations would continue until all possible survivors were accounted for. One sailor reportedly died in hospital, with 78 others wounded.

No group has claimed responsibility for the incident, and the identity of any attacking submarine remains unknown. The event occurs amid heightened regional tensions, including ongoing U.S. operations against Iranian naval assets in the Middle East, though the location falls under the U.S. Indo-Pacific Command's area of responsibility, thousands of miles from those conflict zones.

Iranian state media and officials had not issued a public response as of early Wednesday. Sri Lankan authorities continue search efforts as questions mount over the frigate's fate.