The US attack on an Iranian warship did not violate international law, experts say

The recent U.S. submarine attack on an Iranian warship that killed 87 people likely does not violate international or U.S. military law, according to legal experts, though questions remain about rescue operations following the strike.

The torpedo attack on the IRIS Dena occurred in international waters near Sri Lanka, far from the active conflict zones in the Middle East. Despite the distance from ongoing hostilities, experts maintain the vessel constituted a legitimate military target.

“Targeting a military vessel is not a war crime,” explained Marko Milanovic, professor of international law at the University of Reading in Britain. While Milanovic characterized the broader U.S.-Israeli operations against Iran as “a clear violation of the UN charter,” he noted that the Dena specifically was “a clear military target.”

The Iranian vessel had just participated in naval exercises hosted by India and was traveling through international waters when it was struck. According to Rachel VanLandingham, a professor at Southwestern Law School and retired Air Force lieutenant colonel, these circumstances do not affect the legality of the strike itself.

“It doesn’t matter that it wasn’t firing at the time,” VanLandingham said. “It matters that it can be used to fire at American military assets.”

However, legal experts are raising concerns about what happened after the torpedo hit. International humanitarian law requires military forces to take “all possible measures” to search for and assist wounded or shipwrecked personnel following an attack.

The Pentagon’s own Law of War Manual outlines the same obligation for U.S. naval forces, though it acknowledges “practical limitations” that might apply in certain circumstances. The confined quarters of a submarine and security concerns about allowing foreign military personnel aboard one of the most classified vessels in the U.S. fleet present significant complications.

A U.S. official, speaking on condition of anonymity, confirmed that following the strike, American forces contacted Sri Lankan authorities with the ship’s location to facilitate search and rescue operations. Sri Lanka’s navy responded to a distress signal from the stricken vessel, dispatching ships and aircraft to the area.

“By the time Sri Lanka’s navy reached the location, there was no sign of the ship, only some oil patches and life rafts,” explained Commander Buddhika Sampath, a Sri Lankan navy spokesman. “We found people floating on the water.” The rescue efforts ultimately saved 32 Iranian sailors.

Brian Finucane, who served a decade in the State Department’s Office of the Legal Adviser, emphasized that evaluating the full legality of the operation requires more information about post-attack measures. “The attack may not violate the law of war, but that’s only the start of the analysis,” Finucane said. “What happens after the attack is another matter.”

Eugene R. Fidell, who teaches military law at Yale Law School, suggested that alerting coastal authorities was an appropriate action, but critical questions remain. “It may be a long time before we have a full account of who did what and when in the aftermath of the attack,” Fidell noted, particularly regarding whether rescuers arrived quickly enough to save more lives.

The submarine attack represents a significant escalation in the ongoing tensions between the United States and Iran. It follows a series of reciprocal strikes between the two nations and their allies across the Middle East in recent months. While the U.S. has maintained its right to self-defense against Iranian military assets, the direct targeting of an Iranian naval vessel outside the immediate conflict zone marks a substantial intensification of military operations.

The incident also raises broader questions about the legal framework governing the expanding conflict. While traditional laws of armed conflict apply to specific military engagements, the geographic scope of hostilities between the U.S. and Iran continues to evolve beyond conventional battle spaces.

As international observers await more details about the attack and its aftermath, the legal debate highlights the complex intersection of military necessity, humanitarian obligations, and the practical realities of modern naval warfare.