Counter-swarm technologies and the use of force under the UN charter

Understanding drone swarms and the modern threat landscape

Drone swarms represent a fundamentally different threat category than traditional aerial weapons. A swarm operation involves multiple unmanned aircraft coordinating through shared command systems or autonomous decision-making, attacking simultaneously from multiple vectors. Unlike single drone incidents, swarms overwhelm conventional defenses through sheer volume and coordinated timing.

In January 2026, Russian forces conducted large-scale drone strike campaigns against energy infrastructure, demonstrating how readily available commercial drones are being integrated into coordinated aerial attacks.

Similar incidents have occurred globally, where drone strikes on industrial facilities triggered widespread disruptions. These attacks highlight a critical vulnerability: energy systems, manufacturing facilities, and other essential infrastructure sit at the intersection of national security, economic stability, and public welfare, yet remain highly distributed and difficult to defend against airborne threats.

For your organization, drone swarms present multiple attack vectors beyond simple kinetic destruction, such as surveillance to map security vulnerabilities or the delivery of hazardous payloads.

Unauthorized drones can conduct cyber-physical attacks by hovering near network infrastructure or coordinate with ground-based operations to amplify overall attack effectiveness. The accessibility of commercial drone technology means that both state and non-state actors now possess practical means to conduct coordinated aerial attacks.

Legal tips on drone swarm threats and defense planning

1. What constitutes a drone swarm attack under international law?

A coordinated multi-drone operation qualifies as an "armed attack" under the UN Charter only when it reaches a certain threshold of gravity—typically causing death, injury, or significant physical destruction. Below that threshold, surveillance or disruption activities generally do not trigger the right to state-level self-defense under Article 51, though they may violate civil aviation regulations and privacy laws.

2. Must my company report drone intrusions to authorities?

Yes. Under European and Czech legislation (specifically the Civil Aviation Act and Regulation (EU) 376/2014), safety-related occurrences involving unmanned aircraft must be reported to the Civil Aviation Authority (ÚCL) or police, particularly around critical infrastructure. Failure to report can expose your organization to regulatory penalties and weakens the legal justification for any defensive actions.

3. Can we legally detect drones on our property without special authorization?

Passive detection (radar, acoustic, optical) is generally lawful, provided it complies with data protection laws (GDPR) if personal data (like camera feeds of operators) is processed. However, active interception of drone control signals may violate the Electronic Communications Act regarding privacy of communications. The legality depends heavily on how your detection system handles the data it collects.

Counter-swarm technologies: from detection to active defense

Modern counter-swarm defense operates across a spectrum of technological approaches, each with distinct legal implications. In the European context, the distinction between military and civilian use is strictly enforced.

Detection and monitoring systems represent the lowest-risk approach legally. These include radar arrays, radio frequency sensors, electro-optical systems, and acoustic monitoring that identify and track unauthorized drones without interfering with their operation. These systems act as part of the "U-Space" ecosystem, allowing for rapid identification of drone swarms while maintaining visibility.

Legally, these must comply with GDPR and not infringe on third-party privacy, but they do not require the weapons permits associated with active countermeasures.

Non-kinetic countermeasures (Soft Kill) represent a middle category but face strict regulation. Systems that disable drones through directed energy or jamming fall under the definition of electronic warfare equipment. In the Czech Republic and EU, operating high-power jammers or microwave weapons is generally reserved for state armed forces and police.

Private operation of such devices violates the Act on Electronic Communications and can lead to severe fines from the Czech Telecommunication Office (ČTÚ) for causing interference to authorized radio services.

Kinetic countermeasures (Hard Kill) involve physical destruction through conventional means—projectiles, lasers, or nets. These generate the highest legal and liability risks due to falling debris hazards and risks "Public Endangerment" (Obecné ohrožení) charges under the Criminal Code.

Unlike in some conflict zones, private entities in Europe generally lack the legal authority to unilaterally destroy aircraft, even unmanned ones, unless acting under the strict limits of "Extreme Emergency" (Krajní nouze) or "Necessary Defense" (Nutná obrana) to prevent immediate physical harm.

The practical reality that organizations often overlook is that deploying active countermeasures without specific state authorization can expose your company to criminal liability.

Experts from ARROWS Law Firm handle cases where companies invested in defense technology only to discover that their systems violated aviation or telecommunication regulations.

The UN charter framework: when self-defense becomes legal

International law provides the foundational legal framework that governs when States can lawfully respond to attacks. For private organizations, understanding this is crucial because your right to defend depends on whether the State can authorize you to act.

Article 51 of the UN Charter establishes the inherent right of individual or collective self-defense if an armed attack occurs against a Member of the United Nations.

This applies primarily to States. However, for a private entity defending critical infrastructure, the relevant framework is usually domestic criminal law. Yet, in the context of state-sponsored drone swarms (hybrid warfare), these frameworks merge.

What constitutes an "armed attack"? International jurisprudence suggests that attacks must exceed a minimum threshold of gravity. For drone swarms, mere surveillance does not meet this threshold. However, swarms causing physical destruction to critical infrastructure (power plants, data centers) likely do.

Anticipatory Self-Defense: The debate on whether one can strike before an attack hits is fierce. While the US and Israel often argue for "anticipatory" defense against imminent threats, many European jurisdictions are more restrictive, requiring an attack to be "directly impending" or ongoing.

For a corporation, this means you cannot preemptively destroy drones that are merely hovering nearby unless they pose an immediate, irreversible threat to life or critical safety.

For corporate entities, the danger lies in "Preventive Defense." If you deploy countermeasures against a swarm that might attack but hasn't yet shown hostile intent (e.g., payload release), you risk acting illegally. If your country takes a restrictive position, you may face prosecution for destroying property or interfering with airspace traffic.

Legal tips on self-defense and corporate deployment

1. If our facility is attacked by a drone swarm, can we legally fire back?

Only if the situation meets the strict criteria of "Necessary Defense" under the Criminal Code—meaning the attack directly threatens life, health, or significant property, and the defense is not "manifestly disproportionate." Shooting down a surveillance drone is likely illegal; shooting down a "kamikaze" drone heading for a fuel tank is likely justified.

2. What if we're not sure whether the attack threshold is met?

The law requires you to make a split-second judgment. If you are wrong (e.g., it was a news drone, not a weapon), you bear full criminal and civil liability. This is why automated kinetic defense systems are legally perilous for private actors.

3. Can we use counter-swarm technology to protect our facility from attacks originating in another country?

This becomes a matter of national defense. Private entities should not engage in cross-border hostilities. Such actions should be handed over to the State armed forces. Private engagement could be viewed as an unlawful participation in hostilities.

Proportionality and necessity: the legal constraints on defense

Even when facing a genuine threat, defense must satisfy necessity and proportionality. Necessity requires that the defensive action is the only effective way to avert the attack. If you can protect your assets by moving them, taking cover, or using passive shielding, you legally cannot destroy the drone. Active destruction must be the ultima ratio (last resort).

Proportionality requires that the defense corresponds to the manner of the attack. Under Czech law (§ 29 of the Criminal Code), defense must not be "manifestly disproportionate" to the manner of the attack. 

Using a high-powered jamming system that disrupts local hospital communications to stop a single photography drone is disproportionate, whereas using a net-gun to stop a drone carrying explosives towards a crowd is proportionate.

For organizations deploying counter-swarm systems, this means maintaining comprehensive documentation. You must prove that the system was calibrated to minimize collateral damage and that the decision to engage was based on a reasonable assessment of an immediate threat.

Legal authority to deploy counter-measures: whose permission do you actually need?

This is the most critical compliance trap. In the Czech Republic and most of the EU, the monopoly on the use of force belongs to the State (Police and Army).

Unlike in some interpretations of US law, there is currently no general statutory authority for private companies in the CZ/EU to use active counter-UAS systems simply because they own the property.

Critical Infrastructure: Even operators of critical infrastructure (under the Critical Infrastructure Act) do not automatically have the right to shoot down drones. Defense of these perimeters is typically the responsibility of the Police of the Czech Republic or the Army during crisis states.

Geographical Zones: You can request the establishment of a "Restricted Area" (LKR) or a specific UAS geographical zone (Geo-zone) through the Civil Aviation Authority (ÚCL). This makes unauthorized entry illegal, but enforcement (neutralization) generally remains a police matter.

The practical solution is proactive coordination. You cannot unilaterally deploy a jammer. You must engage with the Civil Aviation Authority (ÚCL), the Czech Telecommunication Office (ČTÚ), and the Police Presidium.

In specific high-risk scenarios, temporary permits for frequency use might be negotiated for testing or specific events, or a Memorandum of Cooperation can be signed where police units with counter-drone capabilities are deployed to your site.

Corporate liability and insurance implications

If your counter-swarm system causes injury or damage, your organization faces strict civil liability. Consider a scenario: Your system jams a drone, which then executes an emergency landing onto a highway, causing a traffic accident. Under the Civil Code, your organization is liable for the damage caused by the operation of the "thing" (the jammer) and the resulting harm.

Standard commercial general liability policies almost universally exclude "acts of war," "terrorism," and often "aviation-related" liabilities.

Furthermore, liability policies often exclude damages caused by intentional acts (like intentionally jamming a signal). Organizations must obtain specialized Aviation Products Liability or specific War/Terrorism coverage that explicitly includes the operation of counter-UAS defensive systems.

Documentation is critical for insurance claims; insurers will demand proof that the system was operated by trained personnel and the deployment was lawful.

Legal tips on insurance and counter-swarm liability

1. Will standard business insurance cover damages from our counter-drone operations?

No. Most policies exclude intentional damage and aviation risks. You need specialized coverage.

2. What documentation does insurance require?

Comprehensive threat assessments, proof of staff training, system maintenance logs, and a legal opinion confirming the lawfulness of your deployment protocols.

3. Can we reduce insurance costs?

Yes. Relying on passive detection + police coordination rather than active kinetic defense significantly reduces liability risk and premiums.

Executive summary for management

Strategic risks require immediate executive attention: Deploying defense systems without understanding the strict EU/Czech regulatory environment creates liability exposure that can exceed the original threat damage.

State Monopoly on Force: Unlike in some other regions, private entities in Europe generally cannot legally deploy active jammers or kinetic weapons. Defense relies on "Necessary Defense" logic in extreme emergencies or police cooperation.

Regulatory fragmentation: You navigate a minefield of Aviation Law (ÚCL), Telecommunications Law (ČTÚ), Criminal Law, and GDPR.

Insurance voids: Standard policies do not cover these activities. Specialized insurance is mandatory.

Legal guidance is essential: ARROWS Law Firm advises on bridging the gap between technical availability and legal reality.

Conclusion of the article

Drone swarm attacks are a genuine threat, but the legal framework in 2026 remains restrictive regarding private defense. The key to effective protection lies not in illegal vigilante action, but in sophisticated detection, legal establishment of restricted zones, and pre-planned coordination with state security forces.

ARROWS Law Firm brings together expertise in security law, aviation regulations, and international compliance to advise organizations on how to build a robust defense strategy that holds up in court.

If your organization faces drone threats, engage legal counsel before purchasing equipment. Contact ARROWS Law Firm at consultation@arws.cz to discuss your specific security environment.

Frequently asked legal questions

1. Our facility was targeted by a drone. Can we use a jammer bought online?

No. Operation of such a device is illegal under the Act on Electronic Communications and can result in massive fines from ČTÚ and potential criminal charges if you interfere with air traffic control or emergency networks.

2. Can we use nets or trained eagles?

Physical interception (nets) is considered a use of force. It is only legal if you can prove "Necessary Defense" against an immediate attack on life or significant property. If you net a drone that was just filming, you are liable for property damage and potentially the crime of Damage to a Thing of Another.

3. We operate in multiple EU countries. Is the law the same?

Generally, yes, under EASA regulations (EU 2019/947), but national enforcement and criminal law nuances vary. The prohibition on private use of electronic warfare is consistent across most of the EU.

4. What if the government authorizes us?

In specific cases of critical infrastructure, the Government can issue specific decrees or the Parliament can pass legislation granting specific powers. However, as of 2026, this is highly specific and rare for private entities. You would need a specific administrative decision granting you such exception, which ARROWS can help investigate.

5. Are we personally liable?

Yes. Executives and security managers can face personal criminal liability for ordering the use of illegal systems that cause harm or violate public safety laws.

6. How do we protect ourselves then?

Invest in high-end detection and identification systems (legally permissible), establish a formal "Geo-zone" restricting flight over your property (legally binding), and sign a coordination agreement with the local Police Directorate for rapid response.