Militant groups have drones. Now what?

Militant groups have a new way to wage war: drone attacks from above. As recent news reports and online videos suggest, organizations like the Islamic State in Iraq and Syria (ISIS) have used commercially-available uninhabited aerial vehicles—better known as UAVs or drones—to drop explosives onto their adversaries in the battle for territory.

That ISIS would weaponize drones shouldn’t be surprising. Militant groups often use the latest consumer technology to make up for capability gaps and level the fight against regular military forces. ISIS broadcasts propaganda through social media platforms like Twitter and Facebook, and plans attacks using encrypted communication platforms like Telegram. This embrace of innovation extends to the way militant groups use military force. Over the last year or so, they have begun to use modified commercial drones for offensive strikes in Iraq, Syria, and Ukraine. These new tools of war provide a way to conduct terror attacks against civilians, and can also pose a threat to ground forces. Stopping drone proliferation is not an option because of the ubiquity of the technology. That means government forces will have to learn to counter drones operated by militant groups, just as they are now training to counter drones used by national militaries.

Already a “daunting” threat. The threat posed by militant groups flying drones is as much about where the threat is coming from—the sky—as it is about the munitions being launched. Militaries fighting militant groups have enjoyed air superiority for decades. US soldiers in Afghanistan and Iraq, for example, have rarely, if ever, feared attacks from the air. Civilians and humanitarian groups in Syria worry about air strikes from Assad’s regime, but not from militant groups like ISIS. The adoption of drones by militant groups is therefore generating a novel challenge. Speaking at a conference in May, Gen. Raymond Thomas, head of the US Special Operations Command, called commercial drones the “most daunting problem” his troops had faced over the previous year. At one point, he said, the anti-ISIS campaign “nearly came to a screeching halt, where literally over 24 hours there were 70 drones in the air.”

Militant groups using modified commercial drones can threaten militaries in more ways than one. In addition to dropping munitions on unsuspecting soldiers, they can strap explosives to drones to generate devastating effects. For example, militants can crash an explosive-laden drone into a target, creating a sort of MacGyvered cruise missile. Alternatively, militants can booby-trap drones. In one case, Kurdish fighters trying to examine a grounded drone died when it exploded. In Ukraine, Russian-backed separatists use drones to target military infrastructure and cause immense damage. For instance, they used a commercial drone to drop a Russian-made thermite hand grenade on an ammunition depot in Eastern Ukraine, causing an inferno and close to $1 billion in damage. Put simply, commercial drones are enabling militant groups to engage in a more diverse array of missions to advance their goals against militarily superior forces.

To be sure, this threat is unlikely to influence any major military power’s ability to win a war. However, even if commercial drones do not ultimately spell victory for militant groups, they can still have military significance. Consider militant groups’ use of improvised explosive devices, also known as IEDs. During the 2000s, IEDs fundamentally shaped the battlefield in Iraq and Afghanistan. There, IEDs caused about 59 percent of all US casualties—8,680 in total, including deaths and injuries—between 2009 and 2011. Moreover, IEDs undermined US counterinsurgency strategy by forcing soldiers into hulking mine-resistant vehicles, protecting soldiers at the cost of close civilian contact, which US strategy suggested was necessary to win hearts and minds. Responding to the IED threat has required billions of dollars in spending, with uncertain impact.

To be clear, commercial drones and IEDs are not the same—one is a platform and the other is a munition, and drones rely more on repurposing technology available to the retail market. But there are similarities as well. First, both technologies are inexpensive, especially compared to the cost of defending ground forces against them. Second, both technologies can be modified in various ways, placing the onus on the defender to adapt to the various configurations militant groups might construct. These two features make both jury-rigged drones and IEDs a concern for any armed force facing a militarily inferior adversary.

Drone wars of the near future. One worrisome potential source of growing drone capacity might seem benevolent at first: the commercial sector itself. As commercially available technology develops at a rapid pace, the variety of military applications is increasing as well. Goldman Sachs recently estimated that between 2016 and 2020, buyers will spend about $100 billion on drones. Defense spending by militaries will account for about $70 billion of that total, but the remaining $30 billion will be made up by consumers, businesses, and civilian government bodies buying commercially-available products.

Within the drone market, the sensor component segment is forecasted to grow the fastest. Sensors can perform a variety of functions, such as transmitting images or detecting heat signatures. Sensors are built for commercial purposes like search-and-rescue operations and crop analysis, but can also be adapted for military purposes. For example, today it is easy to acquire infrared cameras adapted for use on UAVs. It is plausible to imagine a near future in which militant groups program short- or medium-range drones equipped with these sensors to seek and destroy anything with a heat signature. Furthermore, as the drone market grows, more shapes and sizes will become available for purchase. As drones get both bigger and smaller, the variety of military applications expands. Bigger drones can carry larger payloads; for militant groups, this means dropping larger munitions. On the flipside, smaller drones are harder to detect. Militant groups can use them to their advantage by striking targets with minimal warning.

Advances in autonomous systems that enable coordinated behaviors—such as swarming—could also increase the lethality of commercial drones. Swarming robotics lets multiple drones coordinate to achieve a desired behavior, such as turning in formation or attacking a target simultaneously. The US military is testing swarm principles to conduct aerial surveillance, and there are potential applications for strike missions. Commercially, swarm robotics technology has a number of promising applications, from detecting cancer (using swarming nanoparticles) to finding rescue victims. As swarming robotics is mastered and brought to market, the potential applications for militant groups are numerous. For example, militant groups could use the technology to more comprehensively surveil large portions of the battlefield, or attack targets in bombing raids.

Beyond the dangers posed by the creative use of commercially-available technology, military-grade drones may also further spread to militant groups. This has already happened in some places: In the 2000s, Lebanon-based Hezbollah acquired Iranian drones. Considered one of the most operationally effective militant groups in the world, Hezbollah uses Iranian-made drones to surveil Israeli targets. In 2004 and 2006, Israeli fighter jets shot down an Iranian-made Mirsad-1 UAV. And in 2012, an Iranian-made drone operated by Hezbollah managed to invade Israeli airspace and capture images of sensitive nuclear facilities before being shot down. These cases highlight the proliferation of reconnaissance drones. But more countries, including Iran, also now have armed drones, meaning that these, too, could spread more widely. Iran is the most worrisome source of drone proliferation, but other countries seeking to advance their national interests could theoretically deliver drones into the hands of militant groups—for example, it would not be surprising to see Russia export military-grade drones to Ukrainian separatists.

While hardware spreads to militant groups, the transmission of tactical and operational knowledge can also increase their ability to effectively use drones. Whether through training, partnerships with other groups, or mimicry, knowledge will spread. During the Iraq War, Iran’s Quds Force provided Shiite militias with a special IED called an “explosively formed penetrator” and trained them in its use, to devastating effect. Militant groups can also act as sources of information and training to one another in the effective use of crude technologies. Even though ISIS’ territory is decreasing, its soldiers might not be done fighting. There is little reason to believe that the knowledge culled from battle in Iraq and Syria will be lost, especially when considering the historical propensity of jihadi militant forces to jump from conflict zone to conflict zone—from Afghanistan to Chechnya to the Levant and beyond—as well as their current stated desire to continue the fight elsewhere. It seems likely that militant groups’ deadliest “best practices” will endure and spread between battlefields.

What to do. As drones grow in significance on the battlefield, policy makers are thinking about how to effectively counter the threat. Commercial drones are readily accessible and easily purchased, making it nearly impossible to stem the flow of cheap drones into the hands of militant groups. Moreover, targeting the­ experts who can jury-rig simple drones might soon be irrelevant as well. As advanced technologies—like swarming robotics—are mastered and more artificial intelligence is built into even simple commercial systems, “plug and fly” could become the norm for many types of operations. The market will pre-package and directly provide the technical knowledge militant groups need to augment their drones’ capabilities. The engineering skill a particular group needs to effectively use drones will decline. In short, it is not possible to prevent militant groups from getting and using drones. That means nations trying to thwart this threat should focus on defeating it militarily, in particular by detecting, neutralizing, and mitigating the effects of drones in militant hands.

Currently, countries and businesses around the world are grappling with how to best address the challenge in a variety of ways. In Japan, the Tokyo police are using drones equipped with nets to stop potentially hostile drones. The French military and Dutch police are breeding golden eagles to destroy small drones. For its part, the US military tested a “drone-killing laser” and solicited proposals for other solutions to counter unmanned aerial systems. The private sector is developing devices that hack other drones mid-flight, “guns” that jam electromagnetic waves and disrupt enemies’ ability to control their own drones, and compressed-gas-powered launchers that capture targets in a net. To be sure, the Tokyo and Dutch police are unlikely to face off against militant groups, but progress countering drones in one domain is potentially transferable to others. That is why a collective effort by law enforcement, the military, and private sector actors is necessary to mitigate the threat of modified commercial drones used by militant groups or others. It is too early to determine which anti-drone technologies are most promising. However, given the rate at which new drones are entering production, and the many ways militant groups can adapt them for battle, governments should relentlessly pursue any promising lead.

Commercial drones are here to stay—in backyards and battlefields, in the hands of militants and militaries, conducting both surveillance and air strikes. While the advantage belongs to the aggressor in this domain, militaries have good options for addressing the threat.

This column is by Itai Barsade (@ItaiBarsade) and Michael C. Horowitz (@mchorowitz). Barsade is a research fellow at the University of Pennsylvania’s Perry World House, where Horowitz is a professor of political science and associate director.