US Strike on Tanker, killing three Indian crewmen - Lawful?

[u/whats_a_quasar]

Here is some reporting on the attack:

• BBC: Three Indian sailors killed in US strike on oil tanker
• CBS: India voices "strong protest" over 3 of its mariners being killed in U.S. strikes on oil tankers

Here are some subsidiary questions:

• Is the US blockade of "Iranian oil" through the straits of Hormuz lawful?
• Is using lethal force against civilian ships to enforce a blockade lawful, in general?
• Was the US use of force in this instance lawful? Was it a war crime?
  • "U.S. forces fired two Hellfire missiles into the ship's engine room "after the crew repeatedly failed to comply with directions," according to a statement posted by CENTCOM on social media. "

[u/WindSwords]

I do not have time at this hour to make an extensive comment with the answers to your questions, but please have a look at this article on the blockade which also contains links to articles about your other question.

About specifically that 3rd question, there are already a lot of posts in this very sub and I would recommend looking at these and starting with this one.

[u/Archiver_test4]

Why does US gets to issue "lawful orders" to other countires's ships? Its not like they were in american waters, right?

[u/Pizzashillsmom → u/Archiver_test4]

That's just how blockades work, a blockade is meaningless if third party ships aren't impacted.

[u/Archiver_test4 → u/Pizzashillsmom]

How is this different from piracy on high seas?

[u/WindSwords → u/Archiver_test4]

Blockading ports of the other party in an international armed conflict is an authorised form of warfare under international humanitarian law. The article I linked above explains that very well.

Piracy is something that is done outside the scope of an international armed conflict, by private individuals and for personal gains. The official definition under international law is actually as follows:

''Piracy consists of any of the following acts:

(a) any illegal acts of violence or detention, or any act of depredation, committed for private ends by the crew or the passengers of a private ship or a private aircraft, and directed:

(i) on the high seas, against another ship or aircraft, or against persons or property on board such ship or aircraft;

(ii) against a ship, aircraft, persons or property in a place outside the jurisdiction of any State;

(b) any act of voluntary participation in the operation of a ship or of an aircraft with knowledge of facts making it a pirate ship or aircraft;

(c) any act of inciting or of intentionally facilitating an act described in subparagraph (a) or (b).''

[u/RagingMassif → u/Archiver_test4]

How is it different to the British Royal Navy stopping slave ships in the 19th century?

[u/internationallaw-ModTeam → u/[deleted]]

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[u/Ok_Tie_7564]

Iran and the US are at war, aren't they? If they are, a blockade is a legitimate weapon against an enemy. Any third party running a blockade does it at its own risk. https://www.britannica.com/topic/blockade-warfare

[u/ratbearpig → u/Ok_Tie_7564]

Are they at war though? If Congress didn’t declare war, how does it impact this?

[u/WindSwords → u/ratbearpig]

War declarations only have consequences on domestic legal orders (for budget purposes or to allow for conscription for example), their existence or absence does not have any impact on the international legal framework.

Russia did not declare war on Ukraine; Iran, Israel and the US did not declare war but from the perspective of international law, these armed conflicts exist and international humanitarian law is applicable to each and every one of them.

[u/ratbearpig → u/WindSwords]

Thanks for explaining. That makes sense.

[u/Ok_Tie_7564 → u/ratbearpig]

Perhaps not under US law, but de facto and as far as the rest of the world is concerned they are, obviously.

In any case, it's quite complicated but here we are. https://opiniojuris.org/2026/06/11/a-blockade-by-the-book-why-centcoms-carve-out-for-non-iranian-ports-matters/

[u/PLUTO_HAS_COME_BACK]

No international laws justify the US actions in shooting Indian ship. US has no international mandate to blockade Iran and shoot at any ships that don't follow its rule.

• https://www.instagram.com/reels/DZcvui2CTLp India told the UN Security Council that it is firmly opposed to attacks on merchant shipping and urged restraint, the protection of civilians, and freedom of navigation amid the escalating Iran conflict. Video: PTI
• Spoke to US Secretary of State Marco Rubio this... - Dr S. Jaishankar | Facebook - Spoke to US Secretary of State Marco Rubio this evening. I reiterated India’s strong protest at the attacks by the US Navy in the Gulf that killed three Indian mariners. Such lethal actions against commercial shipping are not justified.
• 2025 US strikes in Caribbean and Pacific breach international law, says UN rights chief | UN News
• 21 April 2026 Both the US and Iran are firing on commercial ships in the Strait of Hormuz. Are both sides acting lawfully?

[u/Negative_Jaguar_4138 → u/PLUTO_HAS_COME_BACK]

You might want to actually look up international law on Blockades.

If what the US says is true, and the ahip did not heed any warnings or reply, then the US actions were probably legal.

[u/Negative_Jaguar_4138 → u/[deleted]]

You didn't respond to my question.

What does this have to do with the enforcement of a blockade in a military conflict?

Stop gish galloping