The Iranian warship's final journey before it was sunk by the US

The Iris Dena seen in the Bay of Bengal during the International Fleet Review 2026(Image: AP)

The Indian Navy shared a cheery message on X on February 17. "Welcome!"  It wrote to wish the Iranian warship Iris Dena a warm welcome as it entered Visakhapatnam's port to participate in an international naval gathering. On a clear day, sailors in crisp whites and a grey frigate were captured gliding in the sea harbor. "Bridges of Friendship" and "United Through Oceans" were the hashtags. The ship with 130 crew members sank in the Indian Ocean two weeks later. On March 4, it had been torpedoed by a US submarine off the southern coast of Sri Lanka. The Dena, a Moudge-class frigate of Iran's Southern Fleet that patrols the Strait of Hormuz and the Gulf of Oman, was commissioned in 2021 and was a relatively new vessel. According to US Defence Secretary Pete Hegseth, the vessel "thought it was safe in international waters" but instead "died a quiet death".  At least 87 bodies have been recovered by Sri Lankan rescue teams. Only 32 sailors made it through. The sinking marks a dramatic widening of the war between America, Israel and Iran.  Even though it took place outside of India's control and in international waters of the Indian Ocean, it was awkward for Delhi. "The war has reached our front doors. "That is not a good thing," asserts Arun Kumar Singh, a retired Vice Admiral. The incident has broader repercussions for India's position in the region, according to some strategists. Brahma Chellaney, an expert in Indian strategic affairs, wrote on X that the US torpedoing of the Iranian warship in India's "maritime neighbourhood" was "more than a battlefield episode" and that it was a "strategic embarrassment" for Delhi. Chellaney referred to the incident as a "strategic embarrassment."

Read More: Around 140 people missing after Iranian navy ship sinks off coast of Sri Lanka

"By sinking a vessel returning from an Indian-hosted multilateral exercise, Washington effectively turned India's maritime neighbourhood into a war zone, raising uncomfortable questions about India's authority in its own backyard," Chellaney wrote.

 Just days before its destruction, the Dena had been a diplomatic guest of the Indian Navy.

 The ship was on its way to Visakhapatnam, a sun-kissed port city on India's east coast, for the International Fleet Review 2026 and Exercise Milan, a massive multilateral naval exercise designed to demonstrate India's growing position as a maritime powerhouse. The events, which were attended by 74 nations and 18 warships, were described by Delhi as a demonstration of its desire to become the "preferred security partner" of the Indian Ocean. Visiting ships at such multilateral exercises usually do not carry a full combat load of live munitions, unless scheduled for a live-fire drill, according to Chellaney.  Even during the sea phase, when live firing and drills take place, ships carry only ammunition that is tightly controlled and restricted to the particular exercises. 

Location the US torpedo hits Iranian warship released by Pentagon(Image: BBC)

An invitee to the event, Singh, recalls seeing the warship and its Iranian crew in Visakhapatnam just a few days before the ship changed its fate. He describes the Iranian naval contingent's parade along the seafront as "I saw the boys marching in front of me," just 10 meters away. "All young people.  I'm extremely sad." He claims that the assembled ships, including the Iranian vessel, set sail on February 21 for the sea phase of Exercise Milan, which was supposed to last until February 25. "What transpired following that is less clear; the ship may have returned to port or peeled away following exercises. In any case, the waters off Galle, Sri Lanka, where it was later sunk are only two to three days' sailing time from India's east coast, according to Singh. It is unclear what the ship did in the seven days between.

Submarine commander Singh thinks that the events leading up to the attack were probably straightforward. He points out that vessels are tracked by the United States across all of the oceans in the world. "They would have known exactly when the ship left and where it was heading," he says.  Analysts estimate that one-fourth of the 65-70 submarine fleet in the United States is currently at sea. The Iranian warship had been operating in Sri Lanka's designated search-and-rescue zone about 20 nautical miles (37 kilometers) west of Galle, according to the Indian Navy. According to Singh, the attack appears to have been carried out by a single Mark-48 torpedo, a heavyweight weapon that is capable of splitting a ship in two and containing approximately 650 pounds of high explosive. The submarine may have fired around 05:30 local time, according to video footage. The repercussions were swift and gloomy. According to reports, the warship went down in two to three minutes, leaving little time for rescue efforts. According to Singh, "it's a miracle they managed to send an SOS," which was received by the Colombo-based Sri Lanka Maritime Rescue Coordination Centre. The Indian Navy claims that Colombo picked up an Iranian warship's distress call early on March 4 and launched a regional search-and-rescue operation. The navy said in a statement that Sri Lanka's navy began rescue operations first, while India moved to assist later.

 To help with the search, the Indian Navy sent a long-range maritime patrol plane and kept another plane on standby with life rafts that could be dropped by air. A naval vessel already operating nearby reached the area by late afternoon.  The search for survivors and debris in the water continues on a second ship that joined the effort from the southern Indian port city of Kochi.

An Iranian embassy official (right) in front of Galle National Hospital, where injured sailors are receiving treatment (Image: Reuters)

After a naval attack, countries at war are required by the Second Geneva Convention to take "all possible measures" to rescue wounded or shipwrecked sailors. However, in practice, this duty only applies if a rescue can be attempted without seriously jeopardizing the attacking vessel. Singh says submarines are rarely able to help.

 "Submarines don't surface," he says.  "Someone else can sink you if you surface and give up your position." Singh suspects the speed of the sinking - and possibly sparse shipping in the area at the time - meant few nearby vessels could respond.  He states, "A ship breaking apart that quickly leaves almost no chance." In a shooting war, Singh says, the legal position is blunt.

 Fighting between the United States and Iran had been under way since 28 February, with claims that 17 Iranian naval vessels had already been destroyed.

 He states, "Any ship of a belligerent country becomes fair game when a shooting war is on." Many questions remain.  Why was the Iranian warship still in waters near Sri Lanka nearly a week after leaving India's naval exercise?  Was it returning home or going on a different mission? And how long had the US submarine been tracking it before firing?

 For Delhi, the episode is diplomatically awkward.

 India has drawn closer to Washington on defence while maintaining long-standing political and economic ties with Tehran - a balancing act the war has made harder.

 Despite his general call for "dialogue and diplomacy" to resolve conflicts, Indian Prime Minister Narendra Modi has not addressed the Iranian vessel's sinking or criticized the American strike. Iran's Foreign Minister Abbas Araghchi described the attack as "an atrocity at sea" and stressed that the frigate had been "a guest of India's Navy".  A day after the US attack, another Iranian naval vessel off Sri Lanka's coast has been taken over by Sri Lanka after an engine failure forced it to seek port. The episode has nonetheless sparked debate within India's strategic community.

 Veteran diplomat Kanwal Sibal argued that India's responsibility is moral even though it is not legal.

The sinking of the ship made front page news in Sri Lanka (Image: Reuters)

He wrote on X, "The Iranian ship would not have been where it is if India had not invited it to the Milan exercise." "A word of condolence at the loss of lives of those who were our invitees would be in order."

 Chellaney and others, like him, have presented the problem in a more strategic light. He said that the strike had a negative impact on India's maritime diplomacy. He argued that Delhi's carefully cultivated image as a "preferred security partner" in the Indian Ocean was damaged by the torpedoing of the frigate in "India's maritime backyard." "In one torpedo strike, American hard power has punctured India's carefully cultivated soft power," says Chellaney.

 India's official response remained cautious as the debate accelerated in strategic circles. External Affairs Minister S Jaishankar said on X that he had held a telephone conversation with Araghchi, and also posted a photograph of a meeting with Iran's Deputy Foreign Minister Saeed Khatibzadeh at a foreign policy summit in Delhi.

 For military historian Srinath Raghavan, the legal position is clear: Delhi had no formal responsibility for the Iranian vessel's departure from India's shores. However, ignoring the strategic message is more difficult. "First, the spreading geography of this war.  Second, Raghavan cites India's limited capacity to manage its consequences. "In point of fact, the US Navy has launched a broadside against all regional players, including India,"

Source: BBC