Guest Post: Raul (Pete) Pedrozo on the “Use of Naval Mines During an International Armed Conflict” 

Given recent headlines, you might be asking yourself how much you knew about the law of naval mines.  If the answer is “not enough” today’s post is for you. Retired Navy captain (and popular Lawfire^® contributor!)  Raul (Pete) Pedrozo lays out the law about these deadly devices which pose not only a great threat to warships, but also to merchant vessels.  Get yourself up to speed with this post!

Use of Naval Mines During an International Armed Conflict 

Raul (Pete) Pedrozo

Since Russia’s illegal invasion of Ukraine in 2022, U.S. and ally and partner Navies have reportedly located over 100 sea mines floating in the Black Sea.

Russia purportedly mined the approaches to Ukrainian ports during the initial stages of the war to prevent Ukrainian grain exports from leaving port. Some of these mines, however, have apparently broken loose from their moorings and are dangerously drifting in the shipping lanes in the western Black Sea (NAVAREA Warning 0122/2022, 0092/2022). These mines (likely uncontrolled automatic contact mines) pose a hazard to neutral commercial shipping transporting goods to and from ports in the western Black Sea.

Naval Mines as a Means of Warfare

There are numerous types of naval mines, including moored, tethered, seabed, and controlled mines. Contact mines detonate on contact with a target. Influence mines are detonated through pressure, acoustics, magnetic signatures, electrical fields, ship count, or seismic activity (Newport Manual on the Law of Naval Warfare, § 6.5).

Historically, mines have been used by the belligerents for area denial, coastal and harbor defense, anti-surface and anti-submarine warfare, and blockade. While the use of naval mines as a means of warfare is not prohibited per se, to be lawful under international law, their employment must comply with the law of naval warfare, including the principle of distinction (DoD Law of War Manual, § 13.11; Newport Manual on the Law of Naval Warfare, § 6.5).

Principle of Distinction

When directed against a military objective (e.g., mines designed to hit a specific target), use of naval mines qualifies as an attack and is subject to the rules and principles of targeting law. Consistent with the principle of distinction, means of warfare that constitute an attack can only be directed at military objectives.

Free-floating armed contact mines that are incapable of being directed specifically at a military objective are therefore forbidden by the law of naval warfare due to their indiscriminate effect (NWP 1-14M, ¶ 9.1.2). The mines that have been observed in the Black Sea appear to be either moored or floating automatic contact mines.

1907 Hague VIII Prohibitions

The rules governing the use of automatic contact mines date back to 1907 and are designed to “mitigate the severity of war” and ensure security of peaceful neutral navigation (Hague VIII, preamble).

Hague VIII (which reflects customary international law) forbids the laying of (1) “unanchored automatic contact mines, except when they are so constructed as to become harmless one hour at most after the person who laid them ceases to control them” and (2) “anchored automatic contact mines which do not become harmless as soon as they have broken loose from their moorings.” (Hague VIII, arts. 1(1), 1(2)).

Hague VIII also forbids the laying of “automatic contact mines off the coast and ports of the enemy, with the sole object of intercepting commercial shipping.” (Hague, VIII, art. 2). It is not unlawful, however, to lay mines for some other purpose, such as strategic blockade of enemy ports, coasts, or waterways, even if commercial shipping is incidentally affected (NWP 1-14M, ¶ 9.2.3; DoD Law of War Manual, § 13.11.3.6).

Appropriate Precautions

When laying automatic contact mines, belligerents must take “every possible precaution” to protect peaceful neutral shipping (Hague, VIII, art. 3; DoD Law of War Manual, § 13.11.3.1. In this regard, “belligerents undertake to do their utmost to render these mines harmless within a limited time, and, should they cease to be under surveillance, to notify the danger zones as soon as military exigencies permit, by a notice addressed to ship owners” and to governments through diplomatic channels (Hague, VIII, art. 3; Newport Manual on the Law of Naval Warfare, § 7.2.3.1).

Appropriate precautions can also include surveillance and monitoring of a minefield to reduce the risk of harm to peaceful neutral shipping (DoD Law of War Manual, § 13.11.3.3; Newport Manual on the Law of Naval Warfare, § 7.2.3.1). If a neutral vessel inadvertently sails near the minefield, a belligerent may issue an appropriate warning to the vessel to stand clear of the area.

Additionally, belligerents are obligated to carefully record the location of minefields to facilitate proper notification and subsequent removal or deactivation of the mines at the conclusion of the conflict (NWP 1-14M, ¶ 9.2.3; DoD Law of War Manual, § 13.11.3.4; Newport Manual on the Law of Naval Warfare, § 7.2.3.1).

International notification of the location of armed mines, conducted through official public announcements, communications with the United Nations, bilateral diplomatic notifications, and/or notice to mariners, must be made as soon as military exigencies permit (DoD Law of War Manual, § 13.11.3.2).

Law of Neutrality

The principal right of a neutral State is the inviolability of its territory. This territorial inviolability extends to neutral waters, which include internal waters, the territorial sea, and archipelagic waters of the neutral State (NWP 1-14M, ¶ 7.3; DoD Law of War Manual, §§ 15.7, 15.7.1). During an international armed conflict, belligerents have a duty to respect the inviolability of neutral States (Hague XIII, art. 1; NWP 1-14M, ¶ 7.2; DoD Law of War Manual, § 15.3.1).

Belligerents must also abstain from any act that constitutes a violation of neutrality, such as an act of hostility committed by a belligerent warship in neutral waters (Hague XIII, art. 2). Thus, belligerents may not emplace mines in neutral waters (NWP 1-14M, ¶ 9.2.3; DoD Law of War Manual, § 13.11.3.5; Newport Manual on the Law of Naval Warfare, § 7.2.3.2).

Similarly, when transiting international straits overlapped by neutral waters or archipelagic sea lanes through neutral archipelagic waters, belligerents may not engage in acts of hostility (e.g., laying mines) except in self-defense (NWP 1-14M, ¶¶ 7.3.6, 7.3.7; DoD Law of War Manual, §§ 15.8.1, 15.8.2).

Belligerents may, however, if consistent with the rules pertaining to the use of naval mines, lawfully employ mines beyond neutral territorial seas (e.g., contiguous zone, exclusive economic zone, or high seas), provided there is an alternate route around or through the mine field available for use by neutral shipping with reasonable assurance of safety (NWP 1-14M, ¶¶ 7.3, 7.3.8, 9.2.3; DoD Law of War Manual, §§ 13.11.3.5, 15.7.1).

Similarly, belligerents may employ mines to channelize neutral shipping, to include closing off an international strait or archipelagic sea lanes, but only if an alternative convenient or commercially acceptable route is available for use by neutral shipping (DoD Law of War Manual, § 13.11.3.5; Newport Manual on the Law of Naval Warfare, § 7.2.3.2).

Post-Conflict Removal of Naval Mines

At the conclusion of the conflict, States that employed naval mines are required “to do their utmost to remove the mines which they have laid, each Power removing its own mines.” (Hague, VIII, art. 5; Newport Manual on the Law of Naval Warfare, § 7.2.3.3). A belligerent that has laid automatic contact mines off the coast of another belligerent must provide notice of the position of the mines and each State must expeditiously remove the mines in its own waters (Hague, VIII, art. 5).

States may also enter into a bilateral agreement to remove or deactivate mines at the conclusion of the conflict. For example, Article 2 of the Agreement on Ending the War and Restoring Peace in Vietnam required the United States to “remove, permanently deactivate or destroy all the mines in the territorial waters, ports, harbors, and waterways of North Vietnam.”

Conclusion

Russia’s employment of naval mines in the Black Sea is inconsistent with the rules applicable to the laying of automatic contact mines codified in Hague VII. Russia failed to comply with its international legal obligations to ensure the safety and security of peaceful neutral navigation in the Black Sea.

It appears that numerous anchored automatic contact mines did not become harmless when they broke loose from their moorings, thereby posing a hazard to neutral shipping operating in the western Black Sea.

Use of free-floating automatic contact mines that are incapable of being directed at a specific military objective violates the principle of distinction and is prohibited by the law of naval warfare due to their indiscriminate effect. Although Hague VIII specifically applies only to “automatic contact” mines, the principles contained therein are the only codified rules addressing the laying of conventional naval mines. As such, Hague VIII continues to serve as a general guide for the lawful use of all naval mines.

About the author:

Captain Raul (Pete) Pedrozo, U.S. Navy (Retired), is the Howard S. Levie Chair on the Law of Armed Conflict and professor of international law at the Stockton Center for International Law, U.S. Naval War College. Prof. Pedrozo was the former senior legal adviser at U.S. Pacific Command and served as special assistant to the Under Secretary of Defense for Policy.

Disclaimers:

The views and opinions expressed in this article are those of the author and do not necessarily reflect those of the U.S. Naval War College, the U.S. Department of Defense, or the U.S. Government.

The views expressed by guest authors do not necessarily reflect my views or those of the Center on Law, Ethics and National Security, or Duke University. (See also here).

Remember what we like to say on Lawfire^®: gather the facts, examine the law, evaluate the arguments – and then decide for yourself!