The conflict that has erupted throughout the Middle East including countries in West Asia eventually expanded to include the Iranian Military Marine Corps’s sinking at the hands of an American submarine located in the Indian Ocean, killing dozens of sailors and raising significant geopolitical issues for India and the region.
The warship was called the IRIS Dena and had recently visited Visakhapatnam and participated in a Multinational Naval Exercise hosted by the Indian Navy. Just a few days later, the IRIS Dena was hit by a torpedo from an American submarine while it was returning home from its recent deployment.
How Did This Incident Occur?
On March 4, 2023, at approximately 5:30 AM local time, the American Submarine attacked the Iranian Warship IRIS Dena with a torpedo. The IRIS Dena was approximately 40 Nautical Miles west of the coastal city of Galle, which is located near Sri Lanka’s southern coast.
Although it occurred outside of Sri Lanka’s territorial waters; the attack occurred inside their designated search and rescue area, which means Sri Lanka was in charge of the emergency response operations.
Eventually, 87 bodies were located by search & rescue teams with 32 survivors receiving medical attention. Approximately 60 others are still missing, according to authorities in Sri Lanka.
How The Attack Happened
The US government confirmed the attack publicly.
US Secretary of Defense Pete Hegseth stated that the United States purposely targeted an Iranian military vessel located in international waters.
“Hegseth said to reporters; ” An American submarine sunk an Iranian warship that thought it was safe in international waters. Instead, it was sunk by a torpedo. Quiet death,” Hegseth told reporters, according to The Indian Express.
According to The Indian Express, the footage released from the Pentagon by US military officials showed that this torpedo created a huge explosion which blew the stern of the Iranian vessel up out of the water. This resulted in a rapid sinking of that vessel.
According to General Dan Caine; Chairman of the Joint Chiefs of Staff of the United States, the incident could not be overstated as an historical moment.
General Dan Caine, Chairman, United States Joint Chiefs of Staff stated “For the first time since 1945, a US Navy fast-attack submarine sank an enemy combat ship using a single Mk-48 torpedo,” according to The Indian Express.
The attack is also making worldwide headlines because of the fact that the Iranian Warship IRIS Dena had only previously docked in India and taken part in naval drills hosted there.
According to India Today and The Indian Express, the IRIS Dena docked at Visakhapatnam on February 16 to participate in two major naval events:
- International Fleet Review (IFR)
- MILAN-2026, a multinational naval exercise organised by the Indian Navy
The Indian Navy received the IRIS Dena at Visakhapatnam under extremely positive circumstances, as proclaimed by the Indian Navy: “Indian Navy welcomes IRIS Dena, of the Iranian Navy, on her arrival at Visakhapatnam… reflecting long-standing cultural links between the two nations,” the Indian Navy said in a post cited by India Today.
The exercise was attended by a total of 74 member nations, including Australia, however, members of the USS Pinckney were to participate as guests but before completion were forced to depart without attending.
The exercise ended on February 25, 2023, from this date, the ship began her sails homewards.
The War in Europe
A little over three days after the naval exercise concluded, geopolitical tensions rose and how!
Based on reporting from India Today, a series of American and Israeli air strikes occurred in Iran on February 28, resulting in a full-scale war between both these countries against Iran throughout the Middle East.
The destruction of IRIS Dena from the conflict was an extension into the Indian Ocean, which typically does not see military conflict, away from the Gulf region where tensions have been prevalent.
Sri Lankan-led Recovery Efforts
As Sri Lanka is the designated search and rescue authority for the area of the incident, it took the lead on recovery efforts.
Sri Lankan Foreign Minister Vijitha Herath confirmed the government had quickly launched the recovery mission after receiving distress signals from the sinking vessel.
“We responded to the distress call under our international obligations,” Sri Lankan navy spokesman Commander Buddhika Sampath told reporters, according to The Indian Express.
As part of the rescue effort, the government of Sri Lanka had:
• deployed two naval ships
• deployed one aircraft for reconnaissance and surveillance.
Many of the sailors rescued were found to have suffered serious wounds.
According to Indian Express, several sailors had serious wounds and remained in critical condition due to their immersion in seawater for a long time prior to being rescued.
Rescue personnel were transported to Karapitiya Teaching Hospital in the town of Galle, the largest medical facility in the area.
The Reason a US Submarine was in the Region
U.S. submarines typically operate in The Indian Ocean.
According to a Sri Lankan representative, U.S. Ohio class submarines are generally deployed to patrol the region from Diego Garcia, an important military installation located in the Indian Ocean.
A spokesperson for the United States said Diego Garcia acts as a logistical hub within the United States’ operations in Asia and the Middle East, according to The Indian Express.
Investigators stated they are looking into the events surrounding the assault, including sea tracking data and identified submarine sightings.
The Indian Press has reported that there has also been considerable political reaction to the incident from various political parties in India.
Several opposition leaders expressed concern that the incident raises further questions regarding India’s influence in its own regional waters because the Iranian vessel had been welcomed as a visitor during India’s recent MILAN naval exercise.
Congress Party Representative Pawan Khera questioned, via social media, what action the Indian Government was taking regarding the incident.
“Today, an Iranian naval vessel – returning from the Milan 2026 International Fleet Review, where it had been invited by India – was sunk by a US submarine at the edge of Indian waters near Sri Lanka. Does India have no influence left in its own neighbourhood? Or has that space also been quietly ceded to Washington and Tel Aviv?”
At this time, the Indian Government has not released a detailed official statement regarding the incident.
Why The Location Is Important
The region south of Sri Lanka harbors some of the busiest commercial shipping lanes of any region on earth. Those shipping lanes serve as the conduit for transport between Asia, the Middle East and Europe thus making the region strategically important for conduct of international trade and conduct of naval operations.
Because it is such a strategic region, naval vessels of many countries including India, the US, China, and some others patrol the region on a continual basis.
Sri Lanka itself pursues a neutral foreign policy with regard to international conflict but the geographical location of Sri Lanka places it in the center of major maritime routes.
The Ship That Sank
The IRIS Dena was a Moudge-class vessel of the Iranian Southern Fleet.
The Indian Express reported a defence analyst’s statement that this warship (Qader) is one of the most powerful ships constructed according to the requirements of India. It has several weapons systems including; a 76mm gun, torpedoes, missiles, advanced radar, and multiple target tracking capabilities.
There are facilities for helicopters to land onboard this warship making it a capable warship for patrolling and conducting naval operations in the region.
This is also the first incident since World War II where US submarine forces used torpedoes to sink an enemy warship, according to US sources cited by The Indian Express.