Guest Post: Prof. Pete Pedrozo on “Dangerous Waters: Use of Naval Mines in the Russia-Ukraine Conflict”

How much do you know about naval mines?  If you are like me, the answer may be “not as much as I need to know.”  Today’s post will help you get familiar with an issue of increasing importance. 

Why have naval mines become so critical?  CNBC reports that they are a “big part of the problem” driving the global food shortage.  It says “Russia and Ukraine accuse each other of using the mines to disrupt shipping and prevent grain exports from being able to leave the country.”

In fact, Reuters says 20 million tons of grain are waiting to be shipped, and adds:

As the United Nations tries to broker a path for grain from Ukraine and temper worries about a global food crisis, hundreds of mines laid along the Black Sea present a practical nightmare that will take months to resolve even after any agreement.

The Black Sea is crucial for shipment of grain, oil and oil products. Its waters are shared by Bulgaria, Romania, Georgia and Turkey, as well as Ukraine and Russia.

So what is the law applicable to naval mines?  Fortunately, we have one of the world’s foremost experts on naval law to help us: my friend Professor Raul (Pete) Pedrozo.  Pete is a retired U.S. Navy officer who currently holds the Howard S. Levie Chair on the Law of Armed Conflict, and serves as a professor of international law at the Stockton Center for International Law at the U.S. Naval War College.

Take a few minutes to get up to speed on an issue that is impacting food security around the globe.

Dangerous Waters: Use of Naval Mines in the Russia-Ukraine Conflict

Raul (Pete) Pedrozo

Free-Floating Mines in the Black Sea

On March 3, 2022, the Estonian-owned M/V Helt sank in the Black Sea after it was struck by a mine 20 miles south of Odesa. That same day, the Spanish Hydrographic Office issued a navigational warning (0092/2002) recommending that ships avoid navigating in the northwest part of the Black Sea due to mine danger.

A second warning (0122/22) was subsequently issued cautioning ships about the possibility of drifting mines in the northwest, west, and southwest areas of the Black Sea. Similar warnings were issued by the NATO Shipping Centre.

Later that month, on March 26, the Turkish Navy detected and detonated the first stray mine in the Black Sea off the coast of Istanbul near the Bosphorus Strait, resulting in a temporary closure of the strategic waterway. On March 28, a second drifting mine was detected off the coast of Igneada, near the Bulgarian border, and deactivated by a Turkish Navy dive team.

That same day, the Romanian Navy minesweeper Vice Admiral Constantin Balescu detonated a floating naval mine spotted by a Romanian fishermen about 45 miles off Capu Midia, a Romanian military base located near Constanta. Turkey destroyed a fourth mine on April 6, 2022.

Prior to the discovery of the first drifting mine, the Russian Federal Security Service (FSB) intelligence service warned that “Ukrainian naval forces had deployed barriers of mines around the ports of Odessa, Ochakov, Chernomorsk and Yuzhny.”

The FSB further indicated that the mines had broken lose from their moorings during a storm and that 420 mines were “now floating freely in the western Black Sea” and, given the direction of the currents and wind, could possibly float toward the Bosphrous.

Ukrainian officials denied the Russian allegations, indicating that the drifting mines were Soviet-era naval mines seized in Sevastopol by the Russians when they invaded Crimea in 2014. Ukrainian officials further stated that the mines were intentionally set drift by Russian forces to indiscriminately disrupt commercial shipping in the Black Sea and discredit Ukraine.

Naval Mines

Use of naval mines can be both a means and method of naval warfare. They can be used for area denial, coastal and harbor defense, anti-surface and anti-submarine warfare, and blockade (NWP 1-14M (2022), ¶ 9.2; DoD Law of War Manual (2016), ¶ 13.11.1).

When used exclusively for defensive purposes (e.g., moored mines used in area denial or harbor defense), laying of naval mines is considered a method of naval warfare and does not constitute an attack.

When directed against a military objective (e.g., free-floating mines designed to hit a specific target), use of naval mines is a means of naval warfare that qualifies as an attack and is subject to the rules and principles of targeting law.

For example, the principle of distinction requires means and methods of warfare that constitute an attack only be directed at military objectives. Unless they do something to lose their protected status, civilians and civilian objects may not be attacked.

Therefore, weapons, such as drifting armed contact mines, which are incapable of being directed specifically at a military objective, are forbidden by the law of naval warfare due to their indiscriminate effect (NWP 1-14M (2022), ¶ 9.1.2).

Generally, there are six different categories of naval mines—moored, drifting/floating, bottom, remotely controlled, submarine launched mobile, and rising/rocket mines. The mines being employed in the Black Sea by Russia and the Ukraine appear to be either moored or drifting/floating automatic contact mines.

Applicable Legal Regime

To be a lawful means of naval warfare, the employment of naval mines must adhere to the law of armed conflict. The rules applicable to the use of automatic contract mines are contained in the Convention (VIII) relative to the Laying of Automatic Submarine Contact Mines (Hague VIII).

Neither Russia nor Ukraine are parties to Hague VIII, but these rules reflect customary international law (NWP 1-14M (2022), ¶ and are designed to regulate the employment of mines in order to mitigate the severity of war and ensure the security of peaceful neutral navigation.

Article 1 prohibits the laying of (1) unanchored automatic contact mines unless they “become harmless one hour…after the person who laid them ceases to control them;” and prohibits (2) anchored automatic contact mines that “do not become harmless as soon as they have broken loose from their moorings.”

Belligerents are also prohibited from laying “automatic contact mines off the coast and ports of the enemy, with the sole object of intercepting commercial shipping” (Article 2).

Nonetheless, mining for some other purpose—strategic blockade of enemy ports, coasts, and waterways—is permissible even if commercial shipping is incidentally affected (NWP 1-14M (2022), ¶ 9.2.3; DoD Law of War Manual (2016), ¶ 3.6).

For example, in May 1972, the United States lawfully mined all entrances to North Vietnamese ports to prevent access to, and North Vietnamese naval operations from, these ports. The purpose was to prevent the use of these ports to all shipping—both commercial and military.

The United States provided proper notification to all concerned parties, as well as the United Nations, and neutral shipping was given three days to leave North Vietnamese ports before the mines became active.

The general rule that belligerents must take feasible precautions for the protection of civilians applies when using naval mines (NWP 1-14M (2022), ¶; DoD Law of War Manual (2016), ¶ When employing automatic contact mines, Article 3 requires that the belligerents must take every possible precaution “for the safety of peaceful (neutral) shipping.”

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 (Article 3; NWP 1-14M (2022), ¶ 9.2.3; DoD Law of War Manual (2016), ¶

Ship owners are normally notified of danger zones by a notice to mariners (NOTMAR) or other navigational warning issued pursuant to the International Maritime Organization/International Hydrographic Organization World-Wide Navigational Warning Service (WWNWS). Spain is the NAVAREA Coordinator for the Mediterranean Sea, Black Sea, and Sea of Azov (NAVAREA III).

Feasible precautions may include surveillance and monitoring of minefields by the belligerents to reduce the risk of harm to peaceful neutral shipping (DoD Law of War Manual (2016), If a peaceful neutral vessel inadvertently sails near the minefield, a belligerent may issue an appropriate warning to the vessel to stand clear of the area.

Similarly, belligerents must accurately 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 (2022), ¶ 9.2.3; DoD Law of War Manual (2016), ¶

Neutral states may also lay automatic contact mines during an international armed conflict. If they do so, neutrals must comply with the same rules and take the same precautions applicable to the belligerents (Article 4). Ship owners must be notified in advance of the location of the mines by either a NOTMAR or NAVAREA warning (Article 4). Neutrals must also notify governments through diplomatic channels (Article 4).

At the conclusion of the conflict, states that have laid mines are required “to do their utmost to remove the mines which they have laid, each Power removing its own mines” (Article 5).

If a belligerent has laid anchored automatic contact mines off the coast of the other belligerent, the position of these mines must be notified to the other belligerent and each state must proceed without delay “to remove the mines in its own waters” (Article 5).

Since 1997, a multinational naval mine clearance and ordnance disposal operation has been conducted in the Baltic Sea to clear and destroy naval mines and other explosive remnants from the First and Second World Wars, as well as the Cold War. Of the more than 160,000 naval mines laid in the Baltic Sea during the these wars, only 20 percent have been removed or destroyed.

Removal or deactivation of mines can also be the subject of a bilateral agreement between states. For example, Article 1 of the Protocol to the Agreement on Ending the War and Restoring Peace in Vietnam Concerning the Removal, Permanent Deactivation, or Destruction of Mines in the Territorial Waters, Ports, Harbors, and Waterways of the Democratic Republic of Vietnam requires the United States to “clear all the mines it has placed in the territorial waters, ports, harbors, and waterways of the Democratic Republic of Vietnam.”

Article 1 further requires that the “mine clearing operation…be accomplished by rendering the mines harmless through removal, permanent deactivation, or destruction.”

Additional Limitations on Emplacement of Naval Mines

In addition to the above rules, the emplacement of mines by belligerents may also be regulated by the law of neutrality and the law of the sea. Both Russia and Ukraine are parties to the 1907 Convention (XIII) concerning the Rights and Duties of Neutral Powers in Naval War (Hague XIII) and the 1982 United Nations Convention on the Law of the Sea (UNCLOS).

The law of naval warfare imposes duties and confers rights on neutral and belligerent states. The principal right of a neutral state is the inviolability of its territory. This inviolability extends to neutral waters, which include internal waters, the territorial sea, and archipelagic waters of the neutral state (NWP 1-14M (2022), ¶ 7.3; DoD Law of War Manual (2016), ¶¶ 15.7, 15.7.1).

Belligerents have a corresponding duty to respect the inviolability of neutral states, which are those states that are not taking part in the armed conflict (NWP 1-14M (2022), ¶ 7.2; DoD Law of War Manual (2016), ¶ 15.3.1). Thus, during an international armed conflict, belligerents have a duty to respect the sovereignty of neutral states (Hague XIII, Article 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, Article 1, 2). The belligerents may therefore not emplace mines in neutral waters (NWP 1-14M (2022), ¶ 9.2.3; DoD Law of War Manual (2016), ¶

The contiguous zone and exclusive economic zone (EEZ) do not constitute neutral waters under the law of naval warfare (NWP 1-14M (2022), ¶¶ 7.3, 7.3.8; DoD Law of War Manual (2016), ¶ 15.7.1). While coastal states enjoy limited law enforcement jurisdiction in the contiguous zone (UNCLOS, Article 33) and sovereign rights over resources in the EEZ (UNCLOS, Article 56), UNCLOS does not affect the rights of belligerents under the law of naval warfare.

Rather these zones are subject to high seas freedoms and belligerents may conduct attacks from and within them. Accordingly, belligerents may lawfully employ mines (that can comply with Hague VII rules) beyond the territorial sea of a neutral state (NWP 1-14M (2022), ¶ 7.3; DoD Law of War Manual (2016), ¶

Belligerents retain the right of transit passage through international straits overlapped by neutral waters (UNCLOS, Article 38) and archipelagic sea lanes passage through neutral archipelagic waters (UNCLOS, Article 53).

However, when transiting through the strait or an archipelagic sea lane, belligerent warships and military aircraft must refrain from the threat or use of force against the neutral state, as well as acts of hostility (such as laying mines) and other activities not incident to their transit (NWP 1-14M (2022), ¶¶ 7.3.6, 7.3.7; DoD Law of War Manual (2016), ¶¶ 15.8.1, 15.8.2).

Additionally, while belligerents may employ mines to channelize neutral shipping, they may not do so in a manner that denies these ships the right of transit passage or archipelagic sea lanes passage (DoD Law of War Manual (2016), ¶¶ Thus, closing off a strait or archipelagic sea lane may only be lawful if an alternative convenient route is available for use by neutral shipping.

Naval mines may also be employed to establish limited barred areas in the EEZ or on the 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. Mining of areas of indefinite extent, however, is prohibited (NWP 1-14M (2022), ¶ 9.2.3; DoD Law of War Manual (2016), ¶


Ukraine has admitted to laying mines in the exercise of their right of self-defense, but has not specified the type of mines employed. Clearly, Ukraine may lawfully lay defensive mines in its territorial sea for area denial or harbor defense.

However, if the mines employed by Ukrainian forces are anchored automatic contact mines, they must become harmless as soon as they have broken loose from their moorings. To the extent the Ukraine has employed automatic contact mines that cannot comply with this requirement, they are in violation of the law of armed conflict.

Ukrainian officials allege that the floating mines in the Black Sea are of the R-421-75 type, which were seized by Russian forces at the 174th Armament Base in Sevastopol after Russia annexed Crimea in 2014. The Ukrainian foreign ministry alleges that Russia is sowing the mines in the Black Sea as “uncontrolled drifting ammunition, turning them into a de facto weapon of indiscriminate action.”

Although acknowledging that the origin of the mines remains unclear, the British Ministry of Defense indicated that “it has high confidence that Russian activity” set the mines adrift in the Black Sea. 

To the extent these allegations are true, Russia’s deployment of drifting automatic contact mines, which are incapable of being directed at a specific military objective, violate the principle of distinction and are prohibited by the law of armed conflict due to their indiscriminate effect.

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. The views expressed in this article are his personal views and do not necessarily reflect the views of the United States Government or the Department of Defense.

The views expressed by guest authors do not necessarily reflect the views of the Center on Law, Ethics and National Security, or Duke University.

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

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