The Legal Framework Governing Maritime Conflict
Context:
A recent military incident has brought the legalities of maritime conflict sharply into focus.
A United States submarine torpedoed the Iranian warship IRIS Dena off the coast of Sri Lanka, striking the vessel outside its recognized nautical boundaries.
The Iranian frigate was returning home after actively participating in the International Fleet Review and MILAN-2026—a major multilateral naval exercise organized by the Indian Navy off the coast of Visakhapatnam just last month.
The sinking of the frigate resulted in the tragic deaths of at least 80 sailors and has significantly widened the theatre of the ongoing US-Israel-Iran war.
The conflict has now expanded beyond West Asia and the Gulf, reaching directly into India's immediate neighbourhood
Maritime Security and International Waters:
The incident has ignited a robust debate in India concerning maritime security within the Indian Ocean, a strategic region where New Delhi maintains a very significant naval presence.
However, several Indian Navy officers have pointed out a stark reality:
Once a ship enters international waters, there is very little role any other sovereign country can play in protecting that vessel from an adversarial force.
Although the attack occurred in international waters, it took place within the Exclusive Economic Zone (EEZ) of Sri Lanka.
This geographical proximity to the border enabled Sri Lankan authorities to rapidly deploy and get into search and rescue operations.
An official noted that the ship's position so close to the border might indicate that the crew was already aware of a potential threat.
The Governing Legal Framework:
UNCLOS:
International maritime law primarily falls under the purview of the United Nations Convention on the Law of the Sea (UNCLOS).
Notably, the United States is not a signatory to this foundational maritime treaty.
Presumption of Unlawfulness:
Addressing the legal nuances, Rear Admiral Sudhir Pillai NM (Retd) articulated in a recent essay that the use of military force against a foreign warship on the high seas is "presumptively unlawful".
Such an action can only be considered lawful if it is clearly justified as an act of self-defence or if it occurs as part of an established armed conflict.
UN Charter Article 51:
He further noted that a military strike under these specific circumstances on the high seas could be deemed valid if it successfully met the strict grounds for self-defence outlined under Article 51 of the UN Charter.
Escalation and Tactical Surprise:
Peaceful Passage:
A senior Indian Navy official characterized the US submarine attack as a "big escalation" in the ongoing war.
He stressed that the Iranian warship was on a "peaceful passage" and was entirely outside any active conflict zone when it was targeted.
Even though modern warships are equipped with defensive measures to counter incoming torpedo attacks, the official stated that the Iranian ship was likely taken completely by surprise.
Because the strike occurred early in the morning in international waters, during a peaceful transit, the crew would not have anticipated such an aggressive maneuver.