A vessel operating under the threat of piracy or hostile military action is protected by the

Under international maritime law, specifically the principle of "flag state responsibility," the nation where a vessel is registered (its flag state) has primary jurisdiction and responsibility for that vessel on the high seas. This responsibility includes ensuring the vessel's compliance with international regulations and providing diplomatic and military protection. Therefore, the naval forces of the country of registry are the designated protectors of a vessel flying their flag against threats like piracy or hostile acts.

A. United Nations (UN) military forces: The UN may conduct multinational anti-piracy missions, but it does not have a mandate to protect every individual commercial vessel.
B. country closest to the vessel at the time of attack: A coastal state's jurisdiction is limited to its territorial waters; it has no primary obligation to protect foreign-flagged vessels on the high seas.
C. shipping company registry: The registry is an administrative entity that registers the ship; it does not command naval forces for protection.

- United Nations Convention on the Law of the Sea (UNCLOS), 1982. Article 94, "Duties of the flag State," outlines the state's jurisdiction and control in administrative, technical, and social matters over ships flying its flag. This extends to security.

- APICS CLTD Learning System, Module 3, Section B, Topic 1: Ocean Transport. The module discusses the concept of ship registries (flags of convenience) and the associated responsibilities of the flag state.