Hours after Russia’s invasion of Ukraine began in February, Ukraine’s Ministry of Defense appealed for civilian drone owners to donate or fly their commercially bought drones to help defend Kyiv. Donations poured in and consumer unmanned aerial vehicles (UAVs) took to the skies amid Russia’s advance. Throughout the war, commercial UAVs have been used by Ukrainian regular and special operations forces, Belarusian partisans, Russian infantry, and Russian-led separatists; they demonstrate the challenges, opportunities, and threats emerging from the proliferation of consumer drones. The most common are small, light, and inexpensive rotary-wing quadcopters produced by the Chinese drone maker DJI.

Commercial off-the-shelf (COTS) and homemade drones can offer low-cost and low-risk intelligence, surveillance, and reconnaissance capabilities and are commonly used for target acquisition and for directing artillery or mortar fire. These drones can also be converted into delivery vehicles for improvised explosive devices (IEDs), capable of precision impacts and profound psychological effects. Shortly into the conflict, videos emerged of Ukrainian forces dropping munitions on Russian targets from commercial UAVs, including one popular example where a bomblet was dropped through the sunroof of a Russian vehicle. These aerial attacks employed modernized RKG-3 antitank grenades and VOG-17 fragmentation grenades and successfully targeted and destroyed mechanized and infantry forces.

Ukraine established an impromptu UAV unit following the 2014 Russian invasion when volunteer IT professionals and drone hobbyists came together to form the Aerorozvidka unit. While primarily used for intelligence collection, Aerorozvidka also modifies commercial drones for kinetic strikes, marking Ukraine as one of the first states to develop and use such a tactic. Employment of lethal COTS drones is neither new nor unique to Ukraine or the region. For example, in 2020, Ukrainian forces reported an attack in Donetsk from a COTS drone–dropped grenade, and in the fall of 2021 the Belarusian resistance claimed to have bombed a Minsk police station with a COTS UAV.

The proliferation of small commercial drones represents a dangerous asymmetric threat that Western governments are ill-prepared to counter. The post-9/11 era coincided with information and digital technology revolutions that lowered the barriers of entry for the modification and use of COTS drones. In turn, smaller states and nonstate actors—including terrorist groups, guerrillas, and lone wolves—have developed precision capabilities previously monopolized by advanced militaries. The very nature of commercially available technology means that innovation is diffusing and any creative actor can develop this capability, eroding the advantage of large states and posing new military and security challenges. Cheap commercial drones carrying self-fashioned explosive devices will not remain limited to theaters of war. In essence, these types of drones have become aerial vehicle-borne improvised explosive devices (AVBIEDs).

Counter-AVBIED capabilities are few and far between and existing techniques have not been effectively tested. The materials to create AVBIEDs are cheap, readily accessible, and easily concealed, and can be legally purchased or effortlessly smuggled into Riga, Prague, Stockholm, or Brussels. A malicious actor could attempt a high-profile attack on a busy intersection or crowded marketplace to achieve the psychological effects of a London- or Nice-style terrorist attack that could leave civilians looking to the skies in terror for the rest of their lives. Western governments must learn a critical technical lesson from Ukraine: how to counter AVBIEDs once unleashed on civilian population centers.

The AVBIED: When the Drone Hobbyist Seeks Terror

Terrorist attacks primarily rely on readily available weapons and materials such as small arms and improvised explosives. Remotely detonated IEDs and vehicle-borne IEDs—car bombs—were two attempts to innovate new asymmetric weapons. Since the development of modern drones in the mid to late twentieth century, their use has been monopolized by national militaries. As small drones entered commercial markets in the early 2000s, the remote precision targeting gap has narrowed.

With the emergence of commercially available drones, a new terrorist tool was created—the AVBIED. Unlike their grounded counterparts, AVBIEDs can target remote and restricted areas by navigating a permissive air environment. They are cheap, mobile, and flexible, and in the hands of a relatively skilled operator they can be precise and deadly. Importantly, their missions are not necessarily suicidal for machine or operator. While drones can be employed in single-use, one-way missions (direct AVBIEDs), they can also be outfitted with remotely released explosive ordnance and deployed for multiple missions (indirect AVBIEDs). These latter AVBIEDs can be built with simple, independent release mechanisms to deliver a payload on target and return to a staging area to be resupplied and reused.

Direct AVBIEDs

Direct AVBIEDs conduct kamikaze-style attacks in which the machine is expected to detonate on impact. This crude delivery mechanism dates back to the Cold War, when, in 1971, the Jewish Defense League planned to use a “drone airplane” to target the Soviet Mission to the UN. Another early attempt came in 1977, when according to German media, the Red Army Faction sought to target German politician Franz Josef Strauss with a remote-controlled aircraft.

Many cases of planned attacks with direct AVBIEDs have surfaced over the past two decades, but they were often dismissed as unrealistic or exaggerated. For example, months before he orchestrated the September 11 attacks, Osama bin Laden was believed by some intelligence officials to have been planning an attack on the July 2001 G8 Summit in Italy, targeting President George W. Bush and other world leaders. In another example, during the Second Intifada, the Palestinian Authority reportedly redirected hundreds of toy planes intended for Palestinian children to bomb makers for AVBIED research and development. Both the Revolutionary Armed Forces of Colombia (FARC) and Hamas also began to explore AVBIED programs, though neither became operational. The most significant plot was disrupted in 2011, when al-Qaeda sympathizer Rezwan Ferdaus became the first terrorist convicted and imprisoned for attempting to use a direct AVBIED in an attack on American soil. Ferdaus sought to equip multiple remote-controlled aircraft with explosives to target the US Capitol and Pentagon buildings.

It was not until the Syrian Civil War and the rise of the Islamic State that weaponized drones were successfully deployed by nonstate actors. Although ISIS’s drone program dates back to early 2013, it accelerated rapidly beginning in 2015, when the group stood up a dedicated research and development division. In 2016, ISIS carried out several drone attacks in Iraq, killing two Kurdish fighters and injuring two French soldiers. The tactics spread to groups in Syria, where rebels have attempted to mass direct AVBIED attacks against government forces, and to Mexico, where cartels have adopted AVBIEDs as a tool of intimidation and targeted assassination.

Indirect AVBIEDs

Indirect AVBIEDs are distinguished by the use of an independent release mechanism that enables the drone to drop its munitions and return to the operator. It can thus be reequipped and reused. These AVBIEDs can deliver conventional munitions or can serve as platforms to mount other weapons such as firearms or aerosolized spraying devices. Indirect AVBIEDs are more likely to be used in attacks against smaller or weaker targets due to limited payload, though as demonstrated in Ukraine, they can be effective against vehicles.

The first attempt to develop indirect AVBIEDs occurred in 1995, when Japanese doomsday cult Aum Shinrikyo acquired “at least two radio controlled drone aircraft” in a plan to disperse sarin gas or aerosolized anthrax throughout Tokyo. The next supposed case arose in 2003, when alleged al-Qaeda associate Moazzam Begg was accused of plotting to use a drone for a chemical weapons attack on the British House of Commons. A decade later, Iraq arrested five men planning to use a remote-controlled helicopter to release mustard gas.

Although early attempts to develop indirect AVBIEDs focused on turning UAVs into weapons platforms, today they are primarily used to release conventional munitions. In 2016, Hezbollah first employed commercial UAVs in Aleppo and dropped Chinese-manufactured MZD-2 cluster munitions on Syrian rebel positions. On the other side, Syrian jihadists were also mastering indirect AVBIEDs and modified drones to drop ordnance on proregime forces in Hama. More recently, in Myanmar, the People’s Defense Force has targeted government police stations and training camps by grenades with stabilizing tail fins resembling 3D-printed shuttlecocks from drones, while Houthis have bombed progovernment forces in Yemen with grenade-carrying, DJI Mavic 2 quadcopters.

Commercial Drones in Ukraine

The war in Ukraine has advanced commercial drone war. Even before 2022, Aerorozvidka, the Ukrainian drone unit, was integrated into Ukraine’s armed forces and formally brought weaponized COTS drones into state military services. It developed two types of indirect AVBIEDs: quadcopters generally designed for smaller munitions, such as antipersonnel hand grenades, and octocopters capable of carrying heavier antitank grenades or mortars. Smaller quadcopters can cost less than $1,000, while larger octocopters cost between $5,000 and $20,000. By 2020, Aerorozvidka announced it had successfully attached 3D-printed stabilization fins to RKG-3 antitank grenades to create the RKG-1600. The newly printed tail increased the accuracy of the munitions and enabled the user to drop them from a greater height, reducing the threat of detection, and with greater precision.

Since the war began, innovation in indirect AVBIED capabilities has accelerated, as both sides have found new ways to independently release munitions from COTS UAVs. For example, some Ukrainian units began modifying a piece of fishing gear called tackle feeders to act as a release mechanism for grenades to prevent premature detonation, while Russian-led fighters in the Donbas have begun dropping grenades held in plastic cups. AVBIEDs were used to attack Russian convoys outside of Kyiv and improvised fixed-wing UAVs have also been found. Russian Telegram channels, which have boasted about Russia’s indirect AVBIED capabilities since the start of the war, frequently share videos of Russian service members crudely modifying DJI quadcopters to carry grenades. Large quantities of DJIs have been captured. The conflict has inspired others to create new AVBIED capabilities: Dutch engineers, for example, have designed drum magazine release mechanisms for dropping mortar shells. But the conflict also highlights the need to create counter–small UAV capabilities as states begin to respond to the threat of weaponized consumer drones.

Capabilities to Counter the Threat

Countering these emerging capabilities involves two broad elements: monitoring and countermeasures. Monitoring equipment can be active, passive, or a combination that detects, classifies, locates, and tracks drones in range. Small commercial UAVs are hard to monitor because they are often no bigger than a large bird and possess a low radar signature. Monitoring gear generally cannot distinguish between armed and surveillance drones, but detecting drones and their movement is the first step to providing effective AVBIED responses.

Countermeasures aim to neutralize or destroy a hostile drone. Drones can be neutralized with directional radio frequency jammers, GPS spoofers, or high-power microwave devices; they can be destroyed by high-energy lasers, small arms fire, net guns, or even trained birds of prey. While these are effective against unarmed commercial drones, it becomes more complex with AVBIEDs, depending on payload and range from the target. Since AVBIEDs carry explosive munitions, they are likely to cause damage and casualties unless neutralized or destroyed at a significant distance from an intended target and away from populated areas.

The Ukrainian front lines are seeing the first widespread battlefield testing of counter-AVBIED capabilities. Both small arms fire and directional jammers are being used, with Ukrainian forces introducing the DroneDefender, manufactured by the US company Dedrone, and the Lithuanian “Sky Wiper” EDM4S as nonlethal antidrone jamming guns.

Specific counter-AVBIED tactics, techniques, and procedures cannot be found in publicly available sources. The UK Counter-Unmanned Aircraft Strategy does not mention the word “explosive,” while the US Department of Homeland Security Counter-Unmanned Aircraft Systems Technology Guide only references that commercial drones can carry explosives. The US Department of Defense Counter-Small Unmanned Aircraft Systems Strategy recognizes the importance of responding to the threat of commercial drones but does not explicitly mention the danger of AVBIEDs. With the increasing use of COTS drones for targeted attacks, developing cost-efficient and sustainable countermeasures must become a priority.

Additionally, as advances in commercial technologies continue, we will see increased use of unmanned and autonomous systems. For example, underwater drones are already being used as vehicles for IEDs; last year Hamas attempted to destroy Israeli offshore installations with an explosives-carrying uncrewed submersible. Developing precise and specific countermeasures is a necessity to prevent both targeted attacks against authorities and indiscriminate attacks against civilians.

Moving Forward

As commercial drones become increasingly advanced, accessible, and cheap, the threat from direct and indirect AVBIEDs will become more acute. It is only a matter of time before a state proxy, terrorist group, or lone wolf launches another attack on a high-ranking government official, as a group of rebels attempted in Venezuela in 2018, or an iconic target using an AVBIED. Even if the assault causes minimal casualties, such an event would leave a lasting effect on the public psyche. Large public gatherings and celebrations from the Super Bowl to a Wembley Stadium concert would become instant targets necessary to defend. More sophisticated actors could stage massed and coordinated attacks on the battlefield or on Broadway, where AVBIEDs could swarm a target from multiple directions and overwhelm security forces.

NATO and the governments of its member states should capitalize on recent momentum to organize a study of defensive systems and identify vulnerabilities. NATO could establish a dedicated center of excellence to research, educate, and train member and partner nations on responding to AVBIEDs. Governments must look no further than Ukraine to learn lessons on the threats AVBIEDs will pose in the future of irregular war.

Benjamin Fogel is a graduate student at Johns Hopkins SAIS, with experience at the UN, European Union, and NATO Allied Air Command on Ramstein Air Base. He was named junior ambassador to the 2020 Munich Security Conference and 2022 GLOBSEC young leader.

Andro Mathewson is a research officer at the HALO Trust, focusing on the conflict in Ukraine. He completed his master’s degree in international relations at the University of Edinburgh where he explored the proliferation of underwater drones. Before that, he was a fellow at Perry World House at the University of Pennsylvania. He is starting his PhD in War Studies at Kings College London in September 2022.

The views expressed are those of the authors and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense, or that of any organization the authors are affiliated.

Image credit: Gunnery Sgt. Melissa Marnell, US Marine Corps