In a major escalation in the West Asia crisis, a US submarine on Wednesday torpedoed and sank an Iranian warship in international waters off the coast of Sri Lanka while it was returning after participating in the Milan naval exercise, a multilateral wargame hosted by India.
This marked the first time since World War II that an enemy warship had been sunk by a torpedo. According to a report by Associated Press, citing the Sri Lankan Navy, 87 bodies were recovered after the Iranian warship IRIS Dena sank, while 32 personnel were rescued from the sea.
Ever since the attack, questions have been raised over India’s response to the incident and the security of the vessel, but several factors, international naval guidelines rule out the hosting country’s responsibility under such circumstances for more than one reason. Here’s a detailed look at why linking this event to Indiaโs responsibility is not accurate, either under international maritime rules or in terms of the practical realities governing naval operations at sea.
What is the MILAN Naval exercise?
A major international naval exercise, MILAN 2026, was recently held in Visakhapatnam, organised by the Indian Navy. The exercise brought together naval forces from across the world and was one of the largest maritime engagements hosted by India in recent years.
Navies from multiple countries participated in the exercise, which featured around 42 warships and 29 military aircraft. Among these were 18 foreign warships representing different nations. One of those ships was the Iranian warship, IRIS Dena.
After the exercise concluded in Visakhapatnam, the participating vessels began returning to their respective countries. IRIS Dena was also on its way back when an unexpected and shocking development occurred in the Indian Ocean, near Sri Lanka.
Torpedo attack on an Iranian ship
According to reports, a United States Navy submarine carried out a torpedo attack on IRIS Dena while the vessel was in the region. Within minutes of the strike, the Iranian warship sank into the sea.
The ship reportedly had around 180 sailors on board. Several personnel lost their lives in the attack, while some survivors were rescued by the Sri Lankan Navy during search and rescue operations.
The US Department of Defence stated that this incident marks the first time since World War II that a warship has been sunk through a torpedo attack. Because of this, the incident is being described not only as a naval confrontation but also as a historically significant military moment.
Iran has directly blamed the United States for the attack and has issued a warning in response. At the same time, Iran has highlighted that IRIS Dena had been present in India as a guest vessel of the Indian Navy during the MILAN exercise shortly before the incident.
A wartime issue, and that doesn’t concern India
This detail has been repeatedly emphasised, seemingly as a reminder that the warship had just returned from participating in an Indian hosted naval event.
However, an important principle of international maritime practice needs to be understood in this context.
A warship always remains under the command and operational responsibility of the navy to which it belongs. When a foreign naval vessel visits the port of another country, the host nation is responsible only for security within its territorial waters, that is, within its recognised maritime boundary.
Iranian ship was not in Indian waters
Once a ship leaves those territorial waters and enters the high seas, the responsibility for its safety and protection rests entirely with the navy of the country to which the vessel belongs.
India may host a naval exercise such as MILAN in Visakhapatnam, but it is neither practical nor possible for any country to provide security for every foreign naval vessel across the entire Indian Ocean.
What international naval rules say
International naval rules clearly state that the protection and operational responsibility of a warship lies solely with the nation whose navy operates that vessel.
For this reason, the sinking of IRIS Dena is undoubtedly a tragic incident. The loss of sailors at sea is a serious and deeply concerning event for any nation, and concerns have naturally been expressed in India as well.
At the same time, another reality must also be acknowledged. The incident occurred in international waters, and when examined more closely, it appears to be connected to the wider geopolitical tensions between Iran and the United States.
In that sense, the incident can be seen as an extension of the broader conflict environment in the Middle East that is now spilling into maritime domains.
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