Cluster Munitions and Anti-Personnel Land Mines: An Explainer

Russia’s ongoing invasion of Ukraine has ignited discussions within and between NATO States concerning the international conventions that ban the use, production, transfer, and stockpiling of cluster munitions and anti-personnel landmines, and require the destruction of existing stocks. Perhaps most notably, Lithuania recently withdrew from the 2008 Convention on Cluster Munitions (CCM), a withdrawal that became effective this month. In doing so, it pointed to the threat posed by Russia and the need for operational flexibility in meeting potential Russian aggression. Although numerous NATO States remain party to the CCM, the United States, Turkey, Poland, Estonia, Latvia, Romania, Greece, and Hungary are not. Neither are Russia or Ukraine, and both sides have made use of cluster munitions extensively in the current conflict.

Continuing aggression against Ukraine has also led some NATO States bordering Russia to consider withdrawal from the 1997 Ottawa Convention on anti-personnel land mines, a situation discussed in depth by Sean Watts in his recent Articles of War post. As he explained, the Defence Ministers of Poland, Estonia, Latvia, and Lithuania have recommended doing so. Finland is also contemplating withdrawal, and influential voices in the United Kingdom are asking whether it is time to withdraw from both the CCM and Ottawa Convention. Among NATO States, only the United States is presently a non-party to the instrument. Ukraine is a party, but Russia is not. Many States withdrawing from the Ottawa Convention would still be subject to the strict conditions for using anti-personnel landmines set forth in the 1980 Protocol II and 1996 Amended Protocol II to the 1980 Convention on Conventional Weapons.

The result is a sharp debate over the strategic and operational sensibility of the two conventions in the current Euro-Atlantic security environment. It is an emotive debate, one that pivots between concerns over the existential threat Russia poses to some NATO allies and the humanitarian consequences of the weapons. Leaving aside a discussion of the law to others, this “explainer” is designed to add granularity to the discussions by describing the weapons, their use in general, and their potential employment in the specific context of defending against a Russian invasion. I leave conclusions on the merits of withdrawal, or lack thereof, to the reader.

Cluster Munitions

Cluster munitions are weapons that disperse multiple smaller explosive devices, referred to as bomblets or submunitions, over an area. Aircraft, helicopters, drones, artillery, rockets, ground-based systems, and warships can deliver them. It is helpful to consider the wide variety of cluster munitions in terms of their delivery platform, intended use, and targets profile.

Aircraft are perhaps the best-known delivery platform. For instance, consider the U.S. CBU-105 Sensor Fuzed Weapon, of which the United States retains stockpiles. It disperses ten BLU-108 submunitions, each containing four “Skeet” warheads equipped with sensors that autonomously detect and engage armored vehicles using “explosively formed penetrators” (EFPs). The CBU-105 incorporates self-destruct and self-deactivation mechanisms designed to reduce the risk to civilians of unexploded ordnance, so-called “UXOs.”

Modern artillery-delivered cluster munitions also reflect a trend toward greater precision and reduced residual hazard. The BONUS 155mm artillery shell, developed jointly by France and Sweden, is currently fielded by several NATO States. Each shell releases two winglet-stabilized bomblets equipped with sensors and range-finding technology, capable of autonomously detecting and engaging armored targets. A comparable system, the SMArt 155, employs parachute-retarded submunitions that descend over the target area using infrared sensors and millimeter-wave radar to locate and engage vehicles with top-attack EFPs. These systems are designed in part to lower the dud (failure) rate, which results in UXOs that can pose a risk to civilians after the attack.

In terms of area suppression without submunitions, the U.S. M30A1 Guided Multiple Launch Rocket System-Alternative Warhead (GMLRS-AW) is a rocket system that replaces traditional cluster munitions with a high-explosive warhead containing hundreds of preformed tungsten fragments. While not technically a cluster munition, it is designed to engage personnel and soft-skinned vehicles over a wide area without leaving unexploded ordnance.

A key operational advantage of cluster munitions is their extensive area coverage, making them particularly useful against dispersed, entrenched, area, or moving targets. They are also used for suppression of enemy artillery or air defenses, attacking aircraft on airfields, disruption of enemy supply lines, degrading enemy formations, in situations that are time-sensitive, or when the precise location of a target is not known.

Anti-Personnel Land Mines

Anti-personnel landmines can be broadly grouped into blast and fragmentation mines. Blast mines are pressure-activated mines that explode when stepped upon or otherwise disturbed. For instance, the Russian PMN-4 is an anti-personnel mine buried or concealed on terrain. Upon activation, it detonates a charge that typically severs limbs. Similarly, the U.S. M14 blast mine, which is likewise manually emplaced, contains a relatively small explosive charge intended to disable enemy personnel through lower extremity injury. Like the PMN-4, pressure from someone stepping on the mine triggers it.

Fragmentation mines are designed to incapacitate or kill personnel by dispersing high-velocity fragments across an area. An example is the GATOR mine system. Air delivered, the GATOR scatters both anti-vehicle and anti-personnel mines, like the BLU-92/B, over a target area. The mines have tripwire sensors and self-destruct mechanisms to minimize the long-term risk. Upon contact or disturbance, they detonate, producing a lethal radius of steel fragments.

Although most anti-personnel mines continue to be emplaced manually, scatterable mines (referred to in the U.S. armed forces as the “Family of Scatterable Mines” or FASCAM) can be delivered by aircraft, helicopters, drones, artillery, or rocket systems. For example, the Russian PFM-1, a small blast-type mine, is typically deployed via air-dropped cluster munitions, helicopter-mounted dispensers, or rocket artillery systems. More recently, remote minelaying platforms such as the Zemledelie have also been used to disperse them. The M-139 Volcano mine system, used by U.S. forces, is another example of a scatterable munition system. Deployed from helicopters or ground vehicles, it dispenses both anti-personnel and anti-vehicle mines equipped with self-destruct and self-deactivation features.

Given their mode of emplacement, scatterable mines are often relied upon in developing situations where preplanning the creation of a minefield or other obstacle was not feasible. Because this complicates tracking their location, scatterable mines often have self-destruct or self-deactivation features that deactivate them after a specified period. For instance, the PFM-1S variant has a self-destruct mechanism that activates between one and 40 hours, although this mechanism is often unreliable. The ADAM self-destructs after a preset period ranging from four to 48 hours.

Mines, both anti-personnel and anti-vehicle/tank, are key force multipliers, especially for numerically or otherwise disadvantaged forces. Integrated with other obstacles, they can play an important role in setting up defensive belts. Anti-personnel mines also serve as an effective point deterrent against enemy infiltration into locations such as forward operating bases, airfields, and logistics hubs. Of course, all mines can delay and disrupt enemy advances in so-called “countermobility operations,” especially over key terrain. Aside from the destructive and lethal effects of mines, forces encountering them must proceed cautiously, expending time and effort on mine clearance.

Of note is the use of mines to advantageously shape the battlefield. For instance, minefields can channel enemy forces into predetermined kill zones covered by aircraft, artillery, and other weapons and weapon systems. They can also be employed to deny the enemy use of particular terrain. And scatterable mines are especially useful in dynamic environments, such as when it is crucial to protect a suddenly vulnerable flank, obstruct unanticipated enemy maneuvers, or disrupt a counterattack. Of course, mines also have a substantial psychological impact on enemy forces.

Because mines can also frustrate the maneuver of friendly forces, there is growing emphasis on remotely controlled minefields that allow the selective activation or deactivation of minefields as the situation dictates. For instance, the U.S. M7 Spider Networked Munition System is manually emplaced and remotely controlled. It uses tripwires or sensors to detect intrusions, allowing operators to engage targets from roughly a mile away; it is recoverable and has self-destruct and self-deactivation. The system can be configured with both lethal and non-lethal modules, including flash-bang and smoke effects to deter enemy movement.

As with cluster munitions, mines pose a significant risk to civilians, especially after the immediate military need for their use. This risk has been addressed in Protocol II (1980) and Amended Protocol II (1996) of the 1980 Convention on Certain Conventional Weapons (CCW). All NATO member States and Ukraine are party to both Protocols, although Russia is only party to the first.

Withdrawal from the Ottawa Convention would leave the two Protocols’ requirements, restrictions, and prohibitions in place for States party to them. To address the risks posed by anti-personnel mines, the 1980 Protocol II requires States party to, inter alia, take “all feasible precautions” to safeguard civilians, places restrictions on where and under what circumstances they may be used, requires protective measures like the posting of warning signs and recording and publishing the location where they have been used. Amended Protocol II reinforces and clarifies these obligations. For instance, it prohibits the use of anti-handling devices that function after the mine has ceased to be capable of functioning. It also includes a detailed technical annex dealing with such subjects as recording locations, detectability, self-destruction, and deactivation.

NATO-Russia Conflict Scenarios

As noted, States are rethinking party status vis-à-vis the CCM and Ottawa Convention in light of the potential for a conflict with Russia. The previous discussion addressed the general uses of cluster munitions and mines, including anti-personnel mines. However, the risk of a Russian attack has focused greater attention on their specific use in that context. Four scenarios are especially concerning.

Suwałki Gap Scenario

One of the most significant NATO vulnerabilities is the Suwałki Gap, a 40-mile-wide border linking Poland and Lithuania. Sandwiched between the Russian enclave of Kaliningrad and Belarus, a Russian assault could quickly encircle or isolate it, severing this vital supply line. Adding to the challenge, the constricted geography, limited alternative logistics routes, and lack of substantial defensive depth would limit maneuver by NATO forces defending the Suwałki Gap.

However, the terrain offers opportunities for NATO forces. It is relatively flat, with a mix of open fields, marshy lowlands, and wooded areas, interspersed with numerous rivers and streams, thereby complicating Russian maneuver. The corridor has only a few significant highways. These features offer numerous choke points and ambush zones for delaying and disrupting enemy formations.

Cluster munitions’ ability to saturate areas with anti-personnel and anti-armor submunitions would allow NATO defenders to attack advancing Russian forces along the limited road network and forest-lined approaches, where vehicles would be bottlenecked and highly vulnerable. Sensor-fuzed cluster munitions could target armored vehicles in the dispersed or camouflaged positions this type of terrain affords.

Along the same lines, the terrain’s features would facilitate using anti-personnel land mines to channel Russian forces into kill zones. Scatterable mines could be rapidly utilized to block forest trails, minor roads, and likely bypass routes. This would compel Russian forces to remain on known roads and other significant lines of communication, where they would be more easily attacked, including with cluster munitions.

Indeed, a combination of the two weapons could contribute to establishing successive belts of disruption, attrition, and delay across terrain that offers only limited opportunity for maneuver. The result would be a significant slowing of the Russian advance, affording NATO vital time to mobilize reinforcements and launch counterattacks.

Baltic States Scenario

Due to their geographical proximity to Russia and limited strategic depth, the most vulnerable of the NATO Allies are Estonia, Latvia, and Lithuania. These weaknesses are compounded by the flat or gently rolling Baltic terrain, which is optimal for rapid Russian armor and mechanized maneuver. The three capitals (Tallinn, Riga, and Vilnius), which contain much of the three countries’ critical infrastructure, also would be especially vulnerable, considering the relatively flat terrain surrounding them. Reinforcement by NATO forces before a Russian offensive to seize the area would be problematic, not least because of the Suwałki Gap scenario discussed above. This reality makes slowing Russian forces critical.

Yet terrain that is well-suited for Russian advances is equally suitable for the use of cluster munitions in area denial and disruption operations. Scatterable anti-personnel mines could be employed to establish defensive minefields along the limited roads and logistical routes, slowing the Russian advance and compelling Russian forces to conduct time-consuming mine clearance. Both cluster munitions and mines could contribute to denying the enemy avenues of approach into the capital cities. Mines could also prove invaluable in establishing defensive perimeters around them, thereby frustrating enemy infiltration and protecting supply depots, airfields, and command nodes.

Moreover, beyond the central plains lie forests, bogs, and wetlands. NATO forces could exploit these natural obstacles to channel Russian forces into cluster munition kill zones. To the extent there are routes through them, these could be blocked using preplanned mines.

Southeastern Europe and Black Sea Scenario

In Southeastern Europe, particularly Romania and Bulgaria, a likely scenario involves Russian amphibious and airborne assaults from the Black Sea region. The western Black Sea coast consists of rolling plains with limited natural cover, ideal terrain for amphibious or air-landed operations. The Danube Delta and the Dobruja Plateau (from eastern Romania into northeastern Bulgaria) comprise vast, flat terrain suitable for armored movement and airborne insertion. The presence of significant Russian forces in nearby Crimea heightens this risk. Such operations would allow penetration inland toward key airfields, ports, and logistical hubs. NATO’s southeastern flank would be at significant risk.

Cluster munitions, especially those dropped by NATO aircraft, would likely prove extremely effective in foiling amphibious landings, for armor and mechanized units are highly vulnerable during offloading and when beginning their inland advance. Landing craft would also be susceptible to cluster munitions with anti-armor and anti-personnel submunitions. At the same time, NATO forces could employ anti-personnel cluster munitions against troops on the beach. Cluster munitions would help neutralize the logistics support units, without which the Russian units could not move inland. In the face of such NATO operations, Russian forces would have difficulty consolidating their initial gains and sustaining momentum.

NATO could also foil airborne operations by using anti-personnel cluster munitions or fouling drop zones with mines. Anti-personnel and other mines could also impede Russian use of highways and roads inland and block the limited number of bridges across the Danube and Prut rivers. As in the previous scenarios, they would facilitate the creation of bottlenecks and kill zones and enhance the point defense of key NATO infrastructure.

“High North” Scenario

In a conflict with NATO, Russia would likely conduct operations in the Arctic region to secure routes and infrastructure necessary to control North Atlantic sea lines of communication and limit NATO’s strategic depth. In this regard, Finland shares an over 800-mile border with Russia, the longest of any NATO State. Norway also has an over 100-mile border with Russia. Complicating the operational picture for NATO is the fact that Russia has naval and air bases on or near the Baltic Sea that would facilitate maritime operations and air strikes in the region.

Operations in the area present substantial challenges for both Russian and NATO forces. In particular, the limited road infrastructure in much of the region, the rough terrain, and the harsh environment make maneuvering, conducting resupply, and conducting human-focused operations extremely difficult. NATO forces could exploit some of those challenges by using cluster munitions and mines. And runways and ports are prime targets for attack by cluster munitions.

The Scandinavian Mountains in northern Norway, with their peaks and narrow passes, offer significant choke points that NATO could viably defend; indeed, they amount to natural kill zones for cluster munitions. Mountain passes, valleys, trails, and river crossings are also highly vulnerable to the use of anti-personnel mines for area denial.

Finland’s north, especially Sápmi (also known as Lapland), is heavily forested and interspersed with marshy lowlands and countless lakes. These features restrict off-road mobility, thereby channeling military traffic onto narrow routes that are well-suited for interdiction attacks with cluster munitions and scatterable mines. Moreover, the darkness from autumn to spring would slow Russian airborne and mechanized operations, rendering them vulnerable to attrition operations.

And Russian forces attempting amphibious operations along Norway’s northern coast would have to navigate in narrow fjords and land forces in mountainous coastal terrain. This would make disembarking troops vulnerable to cluster munitions, while anti-personnel landmines could bottle them up by blocking roads and other exits from the landing area. Mines, particularly scatterable ones, could be used throughout the region to foul airborne drop zones and slow movement through forests and across the tundra. Even modest minefields can significantly disrupt enemy operations in terrain that already restricts movement and maneuverability, compelling Russian forces into painstaking, slow-moving clearance actions under harsh weather.

Conclusion

The ongoing reassessment by some NATO States of their participation in the Convention on Cluster Munitions and the Ottawa Convention reflects the Euro-Atlantic region’s complex and evolving security environment. As illustrated by the four scenarios, cluster munitions and anti-personnel land mines, although controversial, offer distinct operational advantages to military forces preparing for the unthinkable, a Russian attack into NATO territory. This is especially so due to the unique capabilities of the weapons to impose delay, attrition, and disruption on the attacking force.

To be clear, I am taking no position here on whether States should remain parties to these conventions or withdraw. Instead, the discussion was offered to inform deliberations by highlighting the specific military considerations likely underpinning the renewed attention on these weapons. Understanding those considerations is a necessary step in evaluating both the risks and the potential benefits of changes in treaty posture.

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Michael N. Schmitt is the G. Norman Lieber Distinguished Scholar at the United States Military Academy at West Point. He is also Professor of Public International Law at the University of Reading and Professor Emeritus and Charles H. Stockton Distinguished Scholar-in-Residence at the United States Naval War College.

The views expressed are those of the author, and do not necessarily reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense. 

Articles of War is a forum for professionals to share opinions and cultivate ideas. Articles of War does not screen articles to fit a particular editorial agenda, nor endorse or advocate material that is published.

 

 

 

 

Photo credit: 24th Mechanized Brigade of the Ukrainian military