U.S. Submarine Sinks Iranian Warship IRIS Dena Near Sri Lanka Amidst Rising Tensions
A U.S. submarine has sunk the Iranian warship IRIS Dena in international waters near Sri Lanka. The incident, confirmed by U.S. Defense Secretary Pete Hegseth, occurred after the Iranian vessel had participated in multilateral naval exercises hosted by India. Sri Lankan authorities conducted rescue operations, recovering bodies and rescuing sailors, while U.S. officials indicated the strike aligned with objectives to reduce Iran's naval capabilities amidst ongoing tensions.
Incident Details
On Wednesday, an Iranian warship, identified as the frigate IRIS Dena, was sunk approximately 40 nautical miles (75 km) off Galle in southern Sri Lanka. The vessel sent a distress call between 6 AM and 7 AM (00:30 to 01:30 GMT).
The U.S. Department of Defense released a video on X showing a torpedo attack, depicting the Iranian ship breaking apart after an underwater explosion.
U.S. Defense Secretary Pete Hegseth stated the sinking demonstrates U.S.-Israeli military operations against Iran extending beyond its borders and described it as a "major blow" to Iran's navy. He also claimed it was the "first such attack on an enemy since World War II." This claim has been contested by reports citing the British HMS Conqueror sinking an Argentine ship in 1982 during the Falklands War and a Pakistani submarine torpedoing an Indian frigate in 1971.
Casualties and Rescue Operations
Sri Lanka's navy responded to the distress signal, dispatching ships and air force planes for rescue. Upon arrival, only oil patches and sailors in the water were found, with no sign of the ship remaining. Sri Lankan authorities reported recovering 87 bodies and rescuing 32 Iranian sailors. These rescued mariners were transported to a hospital in Galle, Sri Lanka.
Reports varied on the number of crew members onboard the IRIS Dena. Iranian Foreign Minister Abbas Araghchi stated the frigate had approximately 130 crew members, while Sri Lankan authorities and other reports indicated around 180 sailors were believed to be on board. An estimated 60 sailors remain unaccounted for. Iranian embassy officials have sent two officers to Galle to gather information from the survivors.
Sri Lankan navy spokespersons indicated that no other ships or aircraft were observed in the area where the Iranian warship sank.
The IRIS Dena and Its Journey
The IRIS Dena was identified as one of Iran's newer warships, reportedly equipped with heavy guns, surface-to-air missiles, anti-ship missiles, and torpedoes, and capable of carrying a helicopter. It had participated in the International Fleet Review and the multilateral naval exercise MILAN 2026, hosted by India in Visakhapatnam from February 15 to February 25. Seventy-four countries reportedly joined these events, and the Iranian warship was documented during these exercises in an X post by the Indian navy. The vessel was reportedly returning to Iran from eastern India when the incident occurred.
Iranian Foreign Minister Araghchi emphasized that the frigate was a guest of India's navy.
U.S. Justification and International Law Perspective
U.S. President Donald Trump has indicated that disabling Iran's navy is a key objective, aligning with U.S. and Israeli efforts to reduce Tehran's naval capabilities. The U.S. cites Iran's attempts to use its naval, ballistic, and drone fleets to potentially close the Strait of Hormuz, a critical global shipping route for oil, as a threat. U.S. General Dan Caine reported that the Pentagon has destroyed 20 Iranian vessels since U.S. and Israeli strikes began, and satellite images of Iranian naval bases reportedly show damaged or sunken vessels.
Donald Rothwell, a professor of International Law, commented that the U.S. likely had the right to target the vessel under existing rules of engagement. However, he noted that torpedoing a vessel far from Iran's territorial waters represents a significant expansion of the conflict's operational area into the Indian Ocean.
Iranian Response
Iranian Foreign Minister Abbas Araghchi accused the U.S. Navy of committing an "atrocity at sea" and stated on social media that the United States "will come to bitterly regret" the attack. While Araghchi made these statements, Iranian leadership has not issued a public comment on the incident. A report from the Australian Naval Institute last year indicated Iran's navy consists of over 18,500 personnel and more than 100 vessels.
Regional and International Context
India's navy and defense ministry confirmed the IRIS Dena's participation in the recent naval exercises. The Indian government has not issued a public statement on the incident. India views the Indian Ocean as crucial for its security and conducts naval patrols and multinational exercises in the region, while also seeking to maintain diplomatic balance regarding U.S.-Iran tensions.
Indian opposition leaders questioned the government's lack of response, with opposition leader Rahul Gandhi criticizing what he termed the "silence" from Prime Minister Narendra Modi's government. Kanwal Sibal, a former Indian foreign secretary, commented on X that while India was not politically or militarily responsible, it had a "moral and human" responsibility, noting the ship was in the waters due to India's invitation.
The incident occurs amid ongoing air strikes by the United States and Israel on Iran, following an attack that reportedly killed Supreme Leader Ali Khamenei and nearly 800 other individuals. Tehran has responded with drone and missile attacks on Israel and U.S.-linked assets in Gulf countries, resulting in multiple fatalities, including six U.S. service members.
Related Naval Incident
Separately, Sri Lanka's media minister, Nalinda Jayatissa, announced that another Iranian ship, the IRIS Bushehr, had entered Sri Lanka's exclusive economic zone after reportedly suffering engine failure. Sri Lankan President Anura Kumara Dissanayake later confirmed that Sri Lankan navy boats began transferring 208 sailors from the IRIS Bushehr to Colombo, and the warship would be taken to an eastern Sri Lankan port. This agreement followed discussions with Iranian officials.