The US sinking of the unarmed Iranian naval vessel, the IRIS Dena, in the Indian Ocean, on March 4, killing most of its crew, was a war crime. The ship’s captain, Commander Abuzar Zarri, and its first officer appeared on an Iranian television interview on April 21, detailing the incident and disputing any claim that the vessel posed a threat.

A Tehran Times article entitled “IRIS Dena sinking: Survivors testimony, diplomatic delays, and US-India-Sri Lanka role” published on May 2 is based on their interviews. It not only makes clear that the US Navy deliberately sunk the vessel after first disabling it, but also points to the complicity of India and Sri Lanka in the criminal attack.

The IRIS Dena, the Iranian frigate, was returning from multinational naval exercises—MILAN 2026—hosted by India when a US submarine attacked. Of the Dena’s 180 naval personnel crew, only 32 were rescued alive by the Sri Lankan coast guard and 84 bodies were recovered from the water.

As the WSWS wrote at the time, the attack amounted to mass murder carried out thousands of kilometres from the Middle East as part of Washington’s escalating war against Iran. “It sent an unmistakable message: the conflict will be prosecuted wherever the US chooses, unconstrained by international law or convention.”

Underscoring this assessment, US War Secretary Pete Hegseth acknowledged the US Navy’s involvement, reportedly describing the operation as a “quiet death.”

On the same day, a second Iranian naval vessel, IRIS Bushehr, carrying 208 crew members, sought permission to enter Colombo Port. After initially refusing entry, the Sri Lankan government allowed the ship to dock on March 5 but only after intense behind-the-scenes diplomatic exchanges.

While Colombo claimed it acted on “humanitarian” grounds as a “neutral” country, it detained 32 survivors from IRIS Dena along with the crew of IRIS Bushehr, according to a Reuters report published on March 7.

Reuters cited an internal US State Department cable dated March 6 in which Chargé d’Affaires Jayne Howell urged that the crew not be repatriated, adding, “Sri Lankan authorities should minimize Iranian attempts to use the detainees for propaganda.”

The Sri Lankan government complied, delaying the return of 84 recovered bodies for over a week and holding the detained the 240 crew members for nearly five weeks, despite repeated requests from Tehran for their repatriation. During their detention, the crew were barred from speaking to the media.

Only after April 14, following a US-declared ceasefire with Iran, were the Iranian naval personnel allowed to leave Sri Lanka and return home.

Speaking after his return, IRIS Dena captain Zarri rejected claims by the US Indo-Pacific Command that the vessel was armed. “One of the exercise’s conditions was that missiles and torpedoes should not be carried by participating vessels,” Zarri said. He confirmed that the frigate carried neither anti-submarine torpedoes nor strategic missiles, leaving it unable to defend itself against an underwater attack.

Zarri said a US submarine launched two torpedoes, with a 90-minute interval between the first and second. The initial strike damaged the ship’s shaft and propeller, bringing Dena to a halt. In the next 90 minutes, the crew carried out emergency procedures while assembling on the aft deck, “preparing for evacuation or surrender.” According to the Tehran Times, the first officer said he “ordered sailors to assemble on the helicopter landing pad while he checked the ship to ensure no one was left behind.”

In a blatant violation of the rules of naval warfare, the US submarine fired a second torpedo even through the ship had been disabled and the crew was visibly preparing to abandon it. The torpedo struck the aft section “directly beneath the assembled crew,” the first officer recalled. “The second torpedo killed 104 of our friends, our comrades, our dear brothers,” Zarri said, adding, “This was their intention”—to leave a maximum number of casualties.

Tehran Times also highlighted the complicity of the governments of India and Sri Lanka in the attack. IRIS Dena, IRIS Bushehr and a third vessel, IRIS Lavan, were participating in the MILAN-2026 exercise and first requested safe harbour from India on February 28—the day that the US-Israeli strikes on Iran began. The request was refused. The following day, New Delhi granted permission for IRIS Lavan to dock at Kochi, but the other two vessels were denied immediate access without explanation.

When the issue arose at the Raisina Dialogue, India’s flagship annual conference on geopolitics and geo-economics on March 9, External Affairs Minister S. Jaishankar did not denounce the US torpedo attack, but instead highlighted the geopolitical volatility in the Indian Ocean and the longstanding US military presence on Diego Garcia.

The Tehran Times explained that India’s refusal to allow the two Iranian naval vessels to dock was a critical factor in the sinking of the IRIS Dena. “Geographically, the delay is difficult to explain. If the squadron had been near Hambantota or Galle in Sri Lanka, the Dena could have reached Kochi in less than 24 hours—or even faster if India had granted access to Tuticorin, a much closer Indian port. At full speed, safety could have been reached within 14 hours.”

Yet India refused despite fully understanding the danger facing the Iranian ships.

The IRIS Dena and IRIS Bushehr then headed toward Sri Lanka, where they had already been invited to visit on February 26. Iranian Ambassador to Sri Lanka Alireza Delkhosh on March 21 told a press briefing in Colombo that the invitation had been made during meetings between Iranian Navy Commander Rear Admiral Shahram Irani and Sri Lanka Navy chief Admiral Kanchana Banagoda on the sidelines of the MILAN exercise.

However, like New Delhi, Colombo did not grant official permission until Dena was sunk. The IRIS Bushehr was only allowed entry on terms dicatated by Washington and Tel Aviv, as indicated in a US embassy cable cited by Reuters. This stands in contrast to repeated claims by President Anura Kumara Dissanayake that his government had acted in a manner that “safeguards the dignity of the country.”

Tehran Times reported that Foreign Minister Vijitha Herath had “acknowledged strong US pressure to block repatriation [of Iranian sailors], including threats involving trade concessions and tariff relief.” Neither this nor the Reuters report has been denied by the Sri Lankan government.

All the evidence—from the technical record of the attack to the harrowing account given by Commander Zarri and his first officer—confirms that the US Navy carried out a deliberate war-crime in torpedoing of an unarmed, immobilised Iranian ship whose crew was in the process of evacuating.

Whether or not they were directly informed of the impending US attack, the Indian and Sri Lankan governments were well aware of the dangers to the Iranian vessels faced. There is no innocent explanation for the delays in allowing them to dock.

The evasions and hypocritical declarations of “neutrality” by Colombo and New Delhi, along with the silence of the imperialist-aligned media, cannot cover-up the fact that these governments were complicit in this US war crime.