IED Classification – Breaking Down Bomb Attacks

By Paul Amoroso, an explosive hazards specialist at Assessed Mitigation Options (AMO) consultancy

INTRODUCTION

This is the second article in a series examining how to develop and sustain an accurate IED threat picture to optimize understanding and ensure the C-IED efforts invested in remain effective as threats evolve. The first article titled, ‘Understanding and Threat Alignment Within a C-IED Enterprise’ emphasised understanding as a vital cross-cutting element of any C-IED enterprise, encompassing two key aspects: the threat itself and the effectiveness of the C-IED efforts invested in. The rest of this series of articles will focus on understanding the threat of IED attacks, through an IED threat picture.

In attempting to develop a system by which an accurate IED picture can initially be developed and subsequently sustained, one approach could be to work off a definition of an IED. While several definitions of an IED are in use, with varying degrees of accuracy and often scripted for specific audiences or contexts, one that is a good fit to generically describe this weapons system is given by: a device placed or fabricated in an improvised manner incorporating destructive, lethal, noxious, pyrotechnic or incendiary chemicals and designed to destroy, incapacitate, harass or distract. It may incorporate military stores but is normally devised from non- military components.1 However, there are aspects of IEDs, and their use not captured in this definition, that would be needed to base an IED threat picture around. For example, IEDs possess the characteristic of being clandestine which is not captured in this definition. As previously noted, definitions of IEDs are often tailored to specific audiences or contexts, resulting in multiple definitions, with little likelihood of consensus within the international C-IED community. This highlights the inherent difficulty in creating a methodology to construct an IED threat picture based solely on a definition.

A more systematic approach to understand IED use in a given context involves examining IED attacks under the headings of their what, how, where, when, who and why. More precisely a comprehensive understanding of the following is required:

  • What components make an IED?
  • Where are IED attacks likely to take place?
  • When are IED attacks likely to take place?
  • Who is involved in IED attacks?
  • Why are IEDs being employed?
  • How are IEDs being employed?

This understanding can be considered the 5W+H of IEDs. This comprehensive analysis helps to attain an understanding of the threat, develop IED analysis tools, and maintain an accurate IED threat picture. Such an approach, helps identify the strengths and weaknesses of an IED system, enabling a threat-aligned C-IED enterprise to make well-informed decisions regarding investments in effective counter-IED efforts. Several subsequent articles in The Counter-IED Report will examine the 5W+H of IEDs as a process in creating a flexible yet systematic approach to developing and maintaining an IED threat picture. This article, however, focuses on examining some common methods used to classify IEDs. It will outline how IEDs and their employment can be analysed from multiple perspectives, each emphasizing particular aspects of their design and use. A key message is that while each classification method has its merits, engaging more than one method of classification allows for a more comprehensive understanding of the technical complexity of IEDs in use. We will begin by discussing the importance of exploring different methods for classifying IEDs, which are essential to developing and maintaining an accurate IED threat picture. A supporting information management system will play a key role in this process, inevitably requiring a database to efficiently organize and manage the necessary data.

DATABASES IN SUPPORT OF AN IED THREAT PICTURE

Any IED threat picture will need to be based upon accurate information of sufficient detail on IED use, the IED system employing them and the context of their use. This will require the capture of data related to these three elements of the IED threat picture and its subsequent analysis as part of some process or intelligence cycle. This will ultimately produce IED intelligence products which can then be used to support the understanding of the C-IED enterprise so that the C-IED efforts invested in remain threat aligned at all times. In terms of IED use, there is a need to understand their technical complexity and their tactical employment. This will necessitate the capture of IED incident data and its input into a database. Databases of IED information and intelligence can be used to find and compare IED incidents. Over time, as the dataset is grown, this will allow for trends, patterns and insights to be obtained. It is such trends, patterns and insights that are needed to develop and sustain an accurate IED threat picture. For an IED database to be useful in informing an IED threat picture, all data entered needs to be structured, systematic and consistent. While advanced comprehensive databases can be designed, some of the challenges which need to be considered include:

  • The vast number of IEDs in terms of their technical complexity and how they can be used in terms of their tactical employment is immense and is a challenge to cover every possible scenario.
  • The acceptance of the likely threat evolution over time owing to action-reaction-counteraction cycle between the IED system and those engaged in the C-IED enterprise.
  • The need for non-specialists in database management, data entry and IEDs to be able to engage with the database in a user friendly and intuitive manner requiring minimal training to do so.

It is for these reasons that when designing an IED database that a systematic and as comprehensive as possible, without being overly complex, system is needed. Applying the KISS principle2 in IED database design is a good approach. This is where the use of IED classification systems can be useful to assist with this challenging endeavour.

IED CLASSIFICATION METHODS

IEDs can be classified3 in multiple ways to account for a large number of design possibilities and tactical employment methods.4 It is unrealistic for every possible IED to be described. However, by applying the KISS principle and utilizing generic classifications with specific examples, it becomes possible to systematically classify IEDs in various ways that are both flexible and practical. The IED threat picture developed and sustained by a C-IED enterprise will ideally speak to its stakeholders which will include specialists and non-specialists at the strategic, operational, and technical / tactical levels. These various audiences will have varying requirements which should ideally be accounted for. By considering IEDs under the following four classifications, a large number of variations is reduced to a manageable number of generic classes which provides understanding for the various stakeholders within the C-IED enterprise and their different requirements:

  • Method of actuation
  • Tactical employment
  • Target effect
  • Technical components

An examination of the first three means of IED classification is provided below with the fourth, classification by technical components, the subject of a subsequent article examining what components make up an IED. We will conclude by examining the issue of classification crossover, emphasizing that the various means of classifying IEDs should not be viewed as isolated or mutually exclusive. Instead, the importance of adopting a flexible and context-driven approach when classifying IEDs is advocated, ensuring that the classification applied best highlights the relevant characteristics within a given context.

Method of Actuation Classification

IEDs can be classified by their actuation method5 which refers to how the IED is designed to be initiated. IEDs can be classified by one of three methods of actuation, namely, time, victim-operated, and command. Below an argument is set out that suicide IEDs are a special category of command IEDs; however, in some systems they are considered as a fourth method. Understanding the method of actuation can provide insight into the most appropriate defeat the device capabilities to be invested in. These three categories of IED actuation method, are also the three categories of IED switch, which can be either a firing or arming switches. IED switches are one of the elements captured under the technical components of an IED.

Time

Time IEDs are those which function after a pre-determined period of time has elapsed. An IED fired after the passing of time allows attackers to be at a safe distance at the moment of initiation, and to escape the scene before security forces can respond. Time IEDs are suitable for static targets such as buildings and installations but limited against moving targets. Another disadvantage of time IEDs is that the intended victims might not be within the danger area when it initiates. However, they still pose a serious threat as tactics can be employed which, draw an unwary target into loitering near it when initiated or they can be employed in indiscriminate attacks, targeting anybody present at a certain location and time.

Victim Operated

A victim-operated IED is an IED with a firing switch that is activated by the actions of an unsuspecting individual, relying on the victim to carry out some form of action that will cause it to function. This method offers the attacker a means to ensure the target is close to the IED when it initiates. The main challenge for the attackers is to find circumstances in which only an intended target will trigger the IED, i.e., an innocent person will not inadvertently trigger it. However, victim operated IEDs may be employed in indiscriminate attacks, targeting anybody at a certain location and time. Victim-operated switches may also be incorporated into IEDs as a secondary means of actuation to target those who attempt to defeat the device.

Command

Command IEDs are those which allow an attacker, often called the triggerman or bomber, to initiate it at a moment of their choosing by completing an action that actuates the firing switch. Command IEDs are especially suited to attacking mobile targets. This author contends that, command IEDs can be categorised under:

  • Emplaced and remotely initiated IEDs
  • Suicide IEDs
    • Bomber initiated
    • Triggerman initiated

The author sees logic considering suicide IEDs, whether involving suicide bombers or proxy bombers, as a form of command IED. This is because their initiation is ultimately controlled by a deliberate action, either by the bomber themselves or by a triggerman monitoring and activating the device remotely. In both cases, a deliberate intended action is necessary to initiate the device. However, delivery of suicide IEDs by a human element adds a layer of complexity that distinguishes them from other command IEDs with their means of employment often needing to be captured also. This highlights the issue of classification crossover which is discussed later.

Emplaced and remotely initiated IEDs

An emplaced6 and remotely initiated command IED involves an attacker selecting two suitable locations: the contact point where the IED will be emplaced, and the firing point from where the triggerman will initiate the device. An emplaced command IED gives the attacker the means to attack a specific target from a safe distance at a moment when initiation will have optimal target effects. There are many methods to initiate an emplaced command IED. Two common methods are by radio control and by command wire. Other methods are possible, for example, pulling a long string. More obscure command firing switches have been used involving the use of various technologies that allow a triggerman to complete an action that causes a firing switch to function from a distance.

Suicide IEDs

A suicide IED is initiated at an attacker’s chosen moment, with an individual carrying the device intentionally killed either as part of the attack or to avoid capture. Both suicide bomber and proxy bomber7 attacks are considered suicide IEDs. The bomber in both cases, is the person involved in transporting or delivering the IED to the point where it is initiated. Suicide IEDs fall under the command actuation method as their initiation ultimately depends on a deliberate action — either by the bomber themselves or by a triggerman remotely controlling the device. This method of command actuation is often closely tied to its delivery mechanism, which may include a person-borne IED (PBIED) or a suicide vehicle-borne IED (SVBIED). Distinguishing between suicide and proxy attacks is frequently challenging until after an attack, leading to significant overlap in the defeat-the-device capabilities developed to counter suicide IEDs.

Bomber Initiated Suicide IEDs

Suicide bomber attacks involve a compliant and cooperative bomber who actively participates in the attack. Suicide bombers provide the ability to circumvent defences by avoiding them and guide an IED to a desired contact point earning them the nickname of ‘guided IEDs.’ Unless neutralised or they have last minute reservations on completing an attack, a suicide bombers is the triggerman in such attacks. Although, proxy bomber attacks involve someone who is not a willing participant in the attack, they may have been intimidated, threatened, or manipulated through forced substance consumption to activate the device against a given target.

Triggerman Initiated Suicide IEDs

There are various reasons and scenarios why a remote trigger is included either as the primary or secondary means of firing a suicide IED. This allows an attacker, other than the bomber, to act as a triggerman with the ability to initiate the device as the primary or secondary (backup)8 means of firing. These scenarios include:

  • A suicide bomber is neutralised prior to having the opportunity to initiate the device.
  • A suicide bomber becomes reluctant to complete their attack.
  • A proxy bomber, despite being threatened, intimidated, or drugged does not carry out the directions given to them.
  • A proxy bomber is unwittingly delivering an IED to a target.
Tactical Employment Classification

Tactical employment is a means of IED classification, in which IEDs are categorised by how the device and target were brought in proximity of each other. It often refers to the method of delivery allowing an understanding of how an attack was intended to be conducted. Tactical employment of IEDs include vehicle-borne; animal-borne; person-borne (proxy or suicide bomber); emplaced; standoff; water-borne; air-borne; and postal IED. It is noted that both water- borne and air-borne refer to their domain of use as much as any other characteristic and are often considered types of standoff IEDs.

Standoff IEDs are a special category of tactical employment of IEDs for several reasons. For this reason, this category of IEDs will be elaborated on in more detail. Standoff IEDs refer to a method of IED employment, involving an explosive device launched or released by an attacker from a safe location, which then travels to its point of contact. Standoff IEDs enable attackers to engage a target without requiring their presence at the point of contact at any stage of the attack. They also allow for the bypassing of physical security measures, such as barriers that prevent the emplacement or delivery of IEDs by other means. Standoff IEDs can be employed across land, air, and maritime domains.

Standoff IEDs can be further classified as unguided and guided. Unguided standoff IEDs, once launched or released, have no means of subsequent control by the attacker. Their targeting relies on their initial positioning, trajectory and often environmental factors that will influence their external ballistics. Unguided standoff IEDs are only suitable for attacking static targets, requiring the attacker to carefully select two locations: its launch or release point and the contact point where it will initiate. They are typically not suitable for attacking mobile targets.

On the other hand, guided standoff IEDs can be controlled in some aspect after launch or release by an attacker, allowing them to adjust their trajectory or placement to a contact point. Examples include remote controlled uncrewed vehicles in the land domain, aerial platforms, more commonly referred to as uncrewed aerial systems (UAS), controlled by an attacker to deliver an IED, and guided surface and subsurface water borne IEDs. Guided standoff IEDs can be used to target both static targets as well as mobile targets. The guidance and control of such standoff IEDs can be linked or unlinked. A linked standoff IED retains a physical link between the attacker at the point of release and the IED,9 while an unlinked standoff IED is controlled by a remote means, typically involving the use of some band of the electromagnetic spectrum at certain frequencies.

In the land domain, standoff IEDs can be delivered using uncrewed vehicles. These vehicles are typically controlled by the attacker, either through linked or unlinked systems, enabling precise guidance to the desired contact point. However, cases of unguided uncrewed vehicles which were not controlled in terms of their movement once released from their launch / release point have been documented. In such cases it is typical for unguided land based standoff IEDs to remain linked to the attacker to allow for the moment of initiation to be controlled.

In the maritime domain, surface and subsurface standoff IEDs can be guided or unguided once released from their launch point. An improvised torpedo is an example of a subsurface unguided standoff IED. Various improvised surface vessels adapted as IEDs are typically controlled to guide them onto their intended target.

In the air domain, there is a far greater variation of standoff IED types. In terms of unguided air standoff IEDs, they may be further classified as direct or indirect. Improvised projectiles fired directly at a target are examples of direct unguided aerial standoff IEDs. Examples include the Provisional IRA’s Mk 16 mortar10 as well their Projected Recoilless Improvised Grenade (PRIG) and their Improvised Projected Grenade (IPG). Improvised mortars and rockets fired with a lobbed trajectory at a target are examples of indirect unguided aerial standoff IEDs. Balloon-borne IEDs are another example of indirect unguided aerial standoff which upon release rely on wind currents to reach their targets, making them unpredictable but can be effective in certain scenarios. Their use has been documented being released in Gaza to target locations in Israel.11

Guided aerial standoff IEDs typically involve some aerial platform (uncrewed aerial system (UAS)12) being used to deliver an IED to a target. UAS may be used in a variety of ways in standoff attacks to deliver explosive effects to a target. These systems are controlled by the attacker until a certain point, where they either release their explosive ordnance onto a target, fire at a target, or crash into a target. The act of releasing explosive ordnance by dropping it onto a target is known as improvised aerial bombing. When a UAS is crashed into its target as a one-way attack it is often referred to as a ‘kamikaze-drone,’ with its explosive payload initiating upon impact.

Target Effect Classification

IEDs can be classified by their intended principal target effect. This classification provides a quick understanding of an attacker’s intended purpose of an attack or, alternatively, the ‘intended, immediate, or direct tactical effect of an IED’13 attack. It can be useful in sending a quick report or organising the immediate response to an attack. Possible intended purposes include anti-armour; anti-personnel; anti-air; anti-infrastructure; anti-vehicle; anti-maritime; tactics, techniques & procedures (TTP) identification; obstacle creation; breaching.

CLASSIFICATION CROSSOVER – FLEXIBLE AND CONTEXT-DRIVEN APPROACH

When classifying IEDs, it is essential to recognize that the various means of classification are not isolated or mutually exclusive. Certain IEDs can fall under multiple categories, depending on the perspective or the lens through which they are being examined. This overlap highlights the importance of avoiding a siloed approach to classification. Instead, the chosen classification should reflect the characteristics most relevant to the context or the specific aspects that need to be emphasized. It is also often advantageous to consider IEDs under multiple systems of classification, especially when addressing more complex devices. These IEDs may exhibit characteristics that overlap across different classification systems, such as their method of actuation, tactical employment, and target effect.

The fact that suicide IEDs are often closely tied to their delivery mechanism, which may include a person-borne IED (PBIED) or a suicide vehicle-borne IED (SVBIED) is an example of the merit of using more than one classification systems for certain IEDs. Examining standoff IEDs further illustrates the reality of IED classification crossover. Classification of standoff IEDs can be complicated owing to the large number of switch types that can be used to launch the IED, arm it and then cause it to initiate i.e. the firing switch. For example, command launch, delay armed, timed aerial burst standoff IEDs have been documented. Firing switch classification can become even more challenging when conventional items of explosive ordnance are employed and function in their original design role e.g. impact initiated or time delay after release. For example, light dependant resistors have been employed to allow for the time delay launch of unguided conventional rockets from improvised launch platforms which function by activation of their conventional impact fuze. A UAS employed standoff IED, may have a timed (delay) arming switch activated after release, with a conventional fuze functioning upon impact into its target. Integration of improvised firing switches with conventional items of explosive ordnance is also known. Hybrid switches14 are often used with aerial standoff IEDs. For example, secondary timed switches can be integrated into standoff IEDs to prevent their capture and subsequent technical exploitation. This can be taken even further with secondary victim operated switches integrated to target any person trying to recover the IED and prevent its exploitation. Classifying an IED as standoff offers valuable insight into its tactical employment. However, this classification can be further refined by incorporating details such as the domain of operation, launch method, arming method, and, where applicable, the specifics of primary and secondary firing switches. This expanded approach adds greater depth and precision to the classification.

By utilizing more than one means of classification when examining IEDs, analysts can more comprehensively capture the features of devices. Detailed understanding of the interplay between delivery and actuation of an IED is particularly valuable in C-IED efforts, as it empowers informed decision making for effective defeat the device capabilities. By adopting a flexible and context-driven approach, IED classification can remain both practical and insightful. Describing an IED through more than one method of classification allows for a more comprehensive understanding of their technical complexity which is a key part of any IED threat picture and in turn informs an understanding of the threat.

CONCLUSION

As part of series of articles examining a methodology for the development and sustainment of an IED threat picture, this article has outlined three IED classification systems in use. It has also introduced the need for a comprehensive understanding of the 5W+H of IEDs to develop such a methodology. Several subsequent articles in The Counter-IED Report will examine the 5W+H of IEDs as a process in creating a flexible yet systematic approach to developing and maintaining an IED threat picture. These six considerations of IEDs will work from the technical (what) to the tactical (how) levels before moving to more operational aspects (where and when and who) prior to examining strategic level considerations (why). The examination of what components make up and IED is linked to the subject of this article, using the fourth named IED classification – technical components. This is the topic of the next article in this series in the curiously titled a ‘A Journey Through PIECES of SPICE PIES‘. ■

FOOTNOTES
  1. United Nations Office for Disarmament Affairs (UNODA) International Ammunition Technical Guidelines (IATG) dated April 2011.
  2. Keep It Simple and Structured as possible.
  3. The act of arranging or organizing a set of objects into groups based on common attributes, characteristics, qualities, traits, capabilities, or features.
  4. A description of how the device and target were brought in proximity of each other. The IED Incident Reporting Guide, 6th Edition.
  5. The terms operation and actuation are sometimes used interchangeably when referring to how an IED is initiated; however, actuation and operation have distinct meanings, particularly in technical contexts. Actuation refers to the process of turning on, starting, activatingi or triggeringii any mechanical, electrical, electronic or chemical device or system. Mechanical actuation can involve turning on or off a motor, opening or closing a valve, moving a lever or switch, and initiating a mechanical timer. Electrical actuation can involve switching on or off an electrical circuit, activating a relay or contactor, powering an electrical device, triggering an electrical signal or alarm, and initiating an electrical process, such as a heating element. Electronic actuation can involve activating a semiconductor device such as a transistor, powering on an electronic circuit, triggering a digital signal or process, engaging an electronic control system and starting an embedded system or microcontroller. Chemical actuation can involve initiating a chemical reaction, starting a catalytic process, activating a chemical sensor or detector and triggering a chemical release mechanism. Actuation focuses on the initiation step. On the other hand, operation refers to the overall functioning or performance of a device or system. It encompasses the entire process from start to finish, including actuation, control, and execution of the intended task. For example, the operation of a machine includes not only turning it on (actuation) but also all the steps involved in its functioning until it completes its task.
    — i. Activation can imply turning on a system or process, making it ready for operation and is frequently used in the context of electrical and chemical devices or systems.
    — ii. Triggering is used to refer to causing an event or action to occur, often used in electronics to start a sequence or response.
  6. An IED that is statically placed where it is likely to be encountered by the intended target. The IED Incident Reporting Guide, 6th Edition.
  7. When a suicide IED is delivered by an individual who has been coerced into carrying out the attack or is unknowingly transporting the device to its target, it is classified as involving a proxy bomber rather than a suicide bomber. The level of control and assurance of success with proxy bombers compared to suicide bombers is lower, as the person delivering the device may not act as directed, or if carrying the device unwittingly, may act in an unplanned manner.
  8. A ‘chicken switch’ refers to the use of a secondary firing switch by a triggerman. This serves as a backup to remotely initiate a suicide IED if the bomber hesitates, fails to act, or is neutralized, ensuring the device functions as intended.
  9. Examples include firing cable or fibre optic cable remaining attached to an IED or it’s delivery platform and unwinding as it moves from the launch / release point to its contact point, retaining a physical connection to the attacker which they use to guide the IED to its target and or control its initiation.
  10. The designation of this projected horizontal shaped charge standoff IED is misleading, as it does not align with the characteristics of a mortar, which is defined by its lobbed trajectory from the launch point to the point of contact.
  11. https://www.terrorism-info.org.il/app/uploads/2020/01/015_20_E.pdf
  12. Often referred to colloquially by the term ‘drone’ which has become a widely recognized and informal term in common use; however, it is not a precise technical term. Drone is also often used colloquially in the water domain also. UAS in this context is taken to include unmanned aerial vehicles (UAV) and remotely piloted aircraft systems (RPAS).
  13. The IED Incident Reporting Guide, 6th Edition.
  14. A hybrid IED switch refers to any switch or number of switches configured as a combination of timed and/or command and/or victim operated switches to act independently and/or dependently on each other.
ABOUT THE AUTHOR

Paul Amoroso is an explosive hazards specialist and has extensive experience as an IED Threat Mitigation Policy Advisor working in East and West Africa. He served in the Irish Army as an IED Disposal and CBRNe officer, up to MNT level, and has extensive tactical, operational, and strategic experience in Peacekeeping Operations in Africa and the Middle East. He has experience in the development of doctrine and policy and was one of the key contributors to the United Nations Improvised Explosive Device Disposal Standards and the United Nations Explosive Ordnance Disposal Military Unit Manual. He works at present in the MENA region on SALW control as well as in wider Africa advising on national and regional C-IED strategies. He has a MSc in Explosive Ordnance Engineering and an MA in Strategic Studies. He runs a consultancy, Assessed Mitigation Options (AMO), which provides advice, support, and training delivery in EOD, C-IED, WAM as well as Personal Security Awareness Training (PSAT) and Hostile Environment Awareness Training (HEAT). This article reflects his own views and not necessarily those of any organisation he has worked for or with in developing these ideas.
LinkedIn profile: https://www.linkedin.com/in/paul-amoroso-msc-ma-miexpe-60a63a42/

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Counter-IED Report, Spring/Summer 2025