IRIS Dena Attack (2026)

Submarine Attack on IRIS Dena Frigate (2026) is a naval attack that resulted in the sinking of the Iranian Navy frigate IRIS Dena by torpedo on 4 March 2026 off the southern coast of Sri Lanka in the Indian Ocean.

The incident occurred off the coast of Galle in southern Sri Lanka. U.S. officials have stated that the attack was carried out by a U.S. Navy submarine using a Mark 48 torpedo.

At the time of the attack, approximately 180 crew members were on board. According to Sri Lankan authorities conducting search and rescue operations, 32 crew members were rescued, 87 were confirmed dead, and some crew members remain missing.

IRIS Dena Vessel of the Iranian Navy - (Social Media)

IRIS Dena Warship

IRIS Dena is a warship of the Iranian Navy classified as a Moudge-class frigate. The vessel served under the Southern Fleet of the Iranian Navy. Its armament includes surface-to-air missiles anti-ship missiles torpedoes and heavy gun systems. It is also known to have a helicopter capacity. The frigate was first commissioned in 2015. The name IRIS Dena is derived from Dena Mountain in southwestern Iran.

IRIS Dena’s operational area within the Iranian Navy primarily covers maritime operations around the Strait of Hormuz and the Sea of Oman. The vessel has been deployed in support of Iran’s naval activities in this region.

Operations and Exercises in the Indian Ocean

IRIS Dena frigate participated in international naval exercises organized by the Indian Navy prior to the attack. The vessel took part in events held as part of the International Fleet Review (IFR) and the Milan-2026 multinational naval exercise.

International Fleet Review is a large-scale naval parade involving warships submarines aircraft and military personnel from multiple countries. Milan-2026 is a multinational naval exercise hosted by India with participation from the navies of numerous nations. More than 85 warships from 74 countries participated in the exercise and IRIS Dena was among the vessels present.

Following the International Fleet Review the IRIS Dena frigate docked at Visakhapatnam port in India on 20 February 2026. This visit was part of diplomatic and military engagements organized by the Indian Navy as part of its international activities.

It has been reported that at the time of the attack the IRIS Dena frigate was returning from exercises in international waters near the southern coast of Sri Lanka and was operating in the Indian Ocean.

The Attack

IRIS Dena frigate was struck by a torpedo on 4 March 2026 while sailing near the southern coast of Sri Lanka close to the city of Galle. The incident occurred within Sri Lanka’s search and rescue zone in the Indian Ocean.

Shortly after the attack the vessel sent an emergency distress call. The call was received off the coast of Galle in southern Sri Lanka. The Sri Lankan Navy and relevant agencies launched a search and rescue operation to evacuate the crew following receipt of the distress signal. Authorities stated that the vessel sank shortly after sending the call. When rescue teams arrived at the scene the ship was no longer visible on the surface and only oil slicks and life raft debris were observed in the water.

On the evening of 4 March U.S. Secretary of Defense Pete Hegseth announced that a U.S. submarine had sunk an Iranian warship with a torpedo in the Indian Ocean. The U.S. Department of Defense confirmed that the attack was carried out using a Mark 48 torpedo.

Search and Rescue Operation

Following the distress call from the IRIS Dena frigate the Sri Lankan Navy launched a search and rescue operation. Sri Lankan naval and air assets were deployed to the incident area to assist in crew evacuation. Maritime and aerial assets were used to locate and recover personnel from the water. Rescue teams pulled survivors from the sea and transported them to shore.

After the sinking of the IRIS Dena frigate the Sri Lankan Navy and Sri Lanka Air Force initiated a search and rescue operation in the area. The operation was conducted off the coast of Galle in southern Sri Lanka. Sri Lankan authorities confirmed that the rescue operation began immediately after receiving the distress call. Sri Lanka’s Minister of Foreign Affairs Vijitha Herath informed parliament that the navy had responded to the call and initiated rescue efforts.

Herath stated that Sri Lankan naval vessels were dispatched to the scene after the distress call was received: “We sent a naval vessel at 06:00 and a second one at 07:00.” When rescue teams arrived at the scene the vessel was no longer visible on the surface. Sri Lankan Navy spokesperson Buddhika Sampath said: “No vessel was found only traces of an oil leak.”

Survivors recovered from the sea were transported to hospitals in Galle city in southern Sri Lanka.

Casualties and Rescued Crew Members

Approximately 180 crew members were on board the IRIS Dena frigate at the time of the incident. Rescue operations conducted by the Sri Lankan Navy and other agencies confirmed that 32 crew members were rescued from the water and taken to hospital.

Sri Lanka’s Minister of Foreign Affairs Vijitha Herath confirmed that 87 crew members had been recovered dead. Sri Lankan Navy spokesperson Buddhika Sampath described how rescue teams located survivors in the water: “We found people floating in the sea and rescued them. Later our investigation confirmed they were from the Iranian vessel.”

U.S. Official Statements

Following the sinking of the IRIS Dena frigate U.S. Secretary of Defense Pete Hegseth announced that an Iranian warship had been sunk by a U.S. Navy submarine using a torpedo in the Indian Ocean.

In his statement Hegseth said a U.S. submarine had sunk an Iranian warship it believed to be in international waters. The U.S. Secretary of Defense also stated that the attack marked the first time since World War II that a hostile warship had been sunk by torpedo.

Speaking at the same press briefing U.S. Chairman of the Joint Chiefs of Staff Dan Caine confirmed that the attack was carried out by a U.S. Navy fast-attack submarine and that the vessel had been sunk by a single Mark 48 torpedo. U.S. officials also stated that multiple Iranian Navy vessels had been targeted as part of military operations against Iran and that these operations were ongoing.

Iran’s Statements

Following the sinking of the IRIS Dena frigate Iranian officials issued statements. Iranian Minister of Foreign Affairs Abbas Araghchi said on social media: “The U.S. committed an act of brutality at sea 2000 miles from Iran’s coast.”

In the same statement Araghchi noted that the IRIS Dena frigate was in the region as a guest of the Indian Navy and that the attack occurred in international waters. The statement added: “The Dena frigate carrying approximately 130 sailors and serving as a guest of the Indian Navy was attacked without any warning in international waters.”

Araghchi further stated regarding the attack: “Note my words: The U.S. will bitterly regret the precedent it has set.”

Sri Lanka’s Decision to Grant Free Visas to Rescued Iranian Seafarers

On 9 March, the Sri Lankan government announced that free one-month visas would be granted to the crew members rescued from the sunken vessel and those evacuated from a second Iranian ship apprehended in nearby waters.

According to the local newspaper Daily Mirror, Sri Lankan Minister of Public Security Ananda Wijepala stated in his remarks on the matter that free visas would be issued to the rescued seafarers under the framework of humanitarian protection to allow them to remain in Sri Lanka.

Wijepala noted that the measure covers a one-month period and emphasized that the decision was not intended to support or harm any party.

Court Decision on the Funerals of Iranian Seafarers Who Lost Their Lives

A court in Sri Lanka ruled that the bodies of the seafarers who died aboard the sunken Iranian vessel must be handed over to Iran’s Embassy in Colombo. The ruling was issued in response to an application filed by the port police in the city of Galle.

Galle Chief Magistrate Sameera Dodangoda ordered that the bodies of the 84 Iranian seafarers held at the hospital be transferred to diplomatic representatives at Iran’s Embassy in Colombo.

It was reported that the bodies are being stored in two mobile cold storage units located within the hospital complex.

Donald Trump’s Remarks on the Operation

U.S. President Donald Trump made remarks regarding consultations he held with U.S. military officials about the sunken vessel in Sri Lankan waters. Speaking at a rally in Kentucky, Trump stated that many crew members lost their lives during the operation and questioned the decision to sink the vessel.

In his speech, Trump said, “I asked them, ‘Why did we kill them? Why didn’t we capture them and put them on our navy?’”

Trump reported that the generals told him these individuals were not suitable for service in the U.S. Navy, adding, “I said, ‘Why must we shoot them?’ One of my generals replied, ‘Sir, it’s more fun.’”