Small Wars Journal

Parade and Event Security

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Parade and Event Security

Christopher Flaherty


Establishing effective parade and event security at mass gatherings, in certain circumstances can involve mitigating a sub-set of terrorist, extremist or violent bombings with an Improvised Explosive Device (IED) classified as in-situ attacks. An in-situ attack occurs where an IED has been used against people who are packed or blocked into a confined space, offering a dense target. The attack results in a higher level of fatal casualties. A core problem with mass gatherings is that these unavoidably create areas where people are blocked together unable to freely move, for a lengthy time. These blocking points can occur outside the formal security exclusion zone, such as at gates (awaiting entry). Other blocking points occur at viewing events or awaiting the start of a parade, even the massing of parade participants (awaiting the start of an event) can constitute a target for an in-situ attack, as was seen at the 2012 Sana’a suicide bombing. The practice of ‘kettling’ is another example of blocking frequently used as a policing tactic, and by events security to establish clear paths between fenced paddocks for onlookers. On-board bus or vehicle bombings also qualify as in-situ attacks. All these examples share similar characteristics. Viewed in terms of tactics, techniques and procedures (TTPs) analysis, this article reviews the problem of how the blocking of people in close confines create opportunities for an in-situ attack to occur. Mitigation strategies will be explored to look at how the opportunity to make an in-situ attack could be reduced.

In-Situ Attack Methodology and Tactics

Called an in-situ attack, this tactic is argued to be the most effective and deadly act of terrorism involving an individual attacker with a relatively small IED as the weapon (Flaherty, 2009; Flaherty and Green, 2011; Bunker and Flaherty, 2013). Historically, in terrorist attacks the fatality to injury proportion is typically quite low and varies from no fatalities to progressively rise to 5% or more, with the bulk of the attack victims being injured only.

A great many variables, such as the type of attack, the IED composition - all impact on the number and proportion of casualties. Nevertheless, there are a smaller sub-set of attacks were there is a more than incremental jump upward to much higher levels of deaths compared to injuries; and appears to be upwards of 20% or more. The common variables, in attacks with high levels of deaths, compared to injuries appear to be situations where attackers choose locations with a large group of people, near each other, and caught in-situ by various physical constraints. Additionally, exposure to potential weaponization of the surrounding environment needs to be considered as a key explanation for the higher level of fatalities seen.

A key tactic in terrorism is micro-level deception (Flaherty, 2003). This can be deception imbued within the environment (Flaherty, 2018a), or that employed by the attacker, affecting the level of situational awareness that people have (Flaherty, 2011). The complicating factor is that an in-situ attack will play-out in seconds. Occurring where people are held in large numbers, close to each other, and in physically cluttered spaces. Individuals in such circumstances are trapped from seeing a potential threat, or rapid get-away. This later point became evident in a study of what people purported to see or hear, just prior to a terrorist attack (Flaherty and Green, 2011). It was found that witnesses commonly recalled seeing the attacker, identifiable by their behaviour etc., however, in some cases, ignored the attacker, and in other cases began to move away from them. The circumstances of the in-situ attack appear to negate the capacity to perceive a threat.

In-situ attacks occur where three sets of circumstances come into play: grouping, proximity, and constraint. It can be observed that the proportion of people killed as opposed to being injured reveals – where groups of people had been attacked in places and are trapped in-situ, we see approximately a 20% jump in the number of dead as compared to the number of wounded; whereas most of the recorded attacks occurred in relatively open locations, where people were easily dispersed resulting in high numbers of wounded but few fatal casualties (Flaherty, 2009; Flaherty and Green, 2011).

The 2013 Boston marathon bombing used the detonation of two IEDs, at an interval of 190 meters, and twelve-to-fourteen seconds apart near the finishing line of the race and was likely intended to target the expected crowding-surge of people near the end. The two IEDs killed three people and injured 264 others. Notwithstanding, the low fatality rate of 1.1%, the event had all the hallmarks of an attempted in-situ attack; albeit a failed one. The placing of the IEDs within the spectator zone behind the race barriers was a likely attempt to capture as many people as possible. The fact that the attack occurred some three hours after the winning runner crossed the finish-line, and not earlier may explain the lower level of fatalities.

From a tactical perspective, the dynamics of an in-situ attack changes the classic military axiom about effective firepower, namely: catching troops in the open affects greater casualties. It is the lack of cover that results in high casualties. In-situ attacks appear to offer two variants, namely: higher casualties are caused caught together in a tight group; and, stopped from moving away, so that the victims are subjected to the full-weapon effect. Dispersion, therefor, becomes a key modifier to the security of mass gatherings.

The dynamics of an in-situ attack changes the traditional public security axiom, namely: crowded places are attractive targets for attacks, as these offer the greater prospect of causing mass casualties. The key tactical drivers for an in-situ attack: grouping, proximity, and constraint, suggests that while the crowding of people is a targeting attractor, there may be within a mass-gathering place various blocking points that are attractive targets, in their own right.

2002 Israel Attacks

Table 1: 2002 Attacks Occurring in Israel: Gives a snapshot of attack events selected from the months of March, April and May. Excluded from Table 1 were shootings, bus bombings and checkpoint attacks. The remaining attacks were chosen for illustrating similar conditions where there was a grouping of people in a market, station or club and approached by a suicide-attacker carrying an IED.

In all the cases illustrated, in Table 1, there are several unknowns, such as the variation introduced by differing blast weights, or the physical circumstances – an indoors club, as opposed to an open-air station etc.

The data presented in Table 1 is placed in one of three bands: where there are no fatalities, and only casualties (band one); fatalities progressively rise 5% or more (band two); deaths compared to injuries occur upwards of 20% or more (band three).


Table 1: 2002 Attacks Occurring in Israel - Source: Author’s analysis of Anti Defamation League/International Policy Institute for Counter-Terrorism (ADL/ICT) database and multiple news reports.

Table 1: Band Two: Attacks that resulted in a lower level of death: 7 March; 21 March; 29 March; 12 April; 19 May; 22 May; and 27 May show fatality levels, from the lowest which was 3.3% (21 March), to the attack of 29 March, which appears to have had a higher level of deaths, some 6.6% killed. In that case, a 16-year-old female Palestinian suicide bomber attacked a Jerusalem supermarket. The attacker appears to have had a more successful deception, as their proximity to shoppers likely did not raise a concern. The 19 May attack involved a Palestinian disguised as an Israeli soldier. It would appear to have been a successful deception strategy. However, due to factors such as lack of crowding, and lack of environment weaponization (Gupta, Lumantarna, Ngo, Mendis, and Flaherty, 2005), this attack appears to have resulted in a lower death rate of 4.8%.

Table 1: Band Three: The events of 2 March; 9 March; 27 March; 31 March; and 8 May show much higher levels of fatalities than compared the lower bands in Table 1. The attacks occurring on 31 March, at the Matza gas station, and 8 May illustrate some of the key characteristics of an in-situ attack. In both cases, these were in-doors, one in a gas station restaurant, the other a crowded club, so impact from reflection of the blast pressure pulse from inside wall surfaces, as well as impact from weaponised debris, was a likely variable. It is also fair to conclude that the people in both cases were relatively constrained by the restaurant or club furnishings from moving. These cluttered environments also aided deception, helping to camouflage the assailant (Flaherty, 2003; 2008). The events of 31 March, at the Matza gas station, and 8 May appear to share some interesting parallels:

  • These spaces are full of fixed infrastructure which stops people in-situ, hence a higher level of fatalities.
  • Circumstances where people did not realise, or were deceived, and people simply stay close to the assailant, when the blast occurred. This implies that the deception used in the attack was significant enough to overcome people’s potential concerns, suspicions or prejudice toward an attacker, and not move away, simply ignoring that was a potential threat (Flaherty and Green, 2011).

Modelling the In-Situ Attack Threat

Parades, at the start and end present key risk areas that require additional security management to mitigate against the possibility of an in-situ attack. These events can involve the mustering of thousands of parade participants in addition to the onlookers. It is arguable that most security thinking about parade events tends to focus on the participant side of the equation, based on the historical assumption that attacks have largely occurred against onlooker participants. However, it is nevertheless important to look at the parade participants themselves as being under threat.

Figure 1: Parade Participants Marching Along Two-Lane Street: Presents a model for understanding an in-situ attack threat, illustrating a portion of parade participants marching along a two-lane street. This is a five-meter length of road flanked by typical street-side pedestrian footpaths. In most urban city areas, the footpaths can be 1.2 meters (and up to two-meters) wide. Motor street lanes are commonly 3.5 meters wide, giving a seven-meter frontage for the marching group. The marching parade participants in Figure 1 are spaced according to the UK event guidance safety crowd limit of two people per square metre (Still, 2018); and this gives around 70 persons occupying a space of 5x7 square-meters. The Figure 1 example can be used to illustrate the threat posed by a larger 2.3 kg pipe bomb, which serves to demonstrate the effect of this in circumstance of an in-situ attack. For instance, it is known that the standard threat stand-off distance is generally 21 meters; and its minimum bomb threat evacuation distance is 130 meters (Commonwealth of Australia, 2017). Extending the Figure 1 example over a 21 meters distance, representing the epicentre for a 2.3 kg pipe bomb detonation, which places some 280+ people within the immediate zone of the blast.


Figure 1: Parade Participants Marching Along Two-Lane Street

Events can involve thousands of participants, packed into relatively small marshalling zones, and the overall probable threat of a successful in-situ attack is relatively high. This problem can be illustrated by the case of the 2012 Sana’a bombing which targeted a parade of Yemeni army soldiers practicing for the annual Unity Day military parade in Yemen.

2012 Sana’a Attack

The 2012 Sana’a attack was a suicide bombing, and it can be characterised as an in-situ attack. It took place at the al-Sabin Square, near Yemen’s presidential palace, as soldiers were arranging themselves for a parade rehearsal. A rogue soldier suicide bomber placed himself among the formed-up soldiers, he was wearing an explosives belt. Reports suggest a significantly powerful blast event resulting in 120 killed, and nearly 350 injured, some of them critically; resulting in a high fatality rate of 25.5%. Notwithstanding that it occurred in an open space, the event markedly resembles the band three levels of fatalities recorded in Table 1. The likely IED blast capacity has not been publicly identified, however a typical waist-belt device can range in the order of 15 to 20 kg TNT equivalent. A photograph taken soon after the bombing shows the immediate impact area of this attack – which shows many of the fatalities clumped together.

Timed when the battalion was closely packed on a tarmac parade ground (which would have likely added to the blast-reflection). Disguised as a soldier, the suicide bomber relied on deception in the attack. The surrounding soldiers were focused on the parade rehearsal instructions. The significance of this later point, is that the soldiers were likely distracted, as was found in the 15 meters, and 11 seconds model:

“This model reduces to a time/action study of approximately the first 11 seconds of an assailant initiating a terrorist attack. This includes modelling behavioural aspects. The scenario involves a person armed with an IED (carried in a backpack), who moves toward a group of people. He or she then takes out their mobile phone and rings a number which initiates the blast event. This takes approximately 8.20 seconds to complete. This act, like the demeanour of the assailant is taken to have deception qualities, that is, the assailant is sufficiently hiding his or her true intentions so as to not tip-off would-be victims. The question is: will others see this as a threat and move out of the immediate lethal zone (in this case calculated to be 15 meters out from Point-of-Detonation at Zero). This distance can be traversed in approximately 11 seconds for an able person (walking the average human speed of 1.3 meters per second). If a person perceives something is wrong and there is sufficient time for action and not confined, the person will avoid being fatally injured.” (Flaherty and Green, 2011)

The bands one, and two attacks listed in Table 1 illustrate the significance of dispersion of potential victims as a way to counteract the use of an in-situ attack. Either an attack is made when people are moving, and dispersed, or are dispersing which results in many injured, and few fatalities; or the attack is made when people are stationary and confined together which results in high levels of fatality. Dispersion is advanced as a significant strategy in mass gathering security. In particular, rejecting the notion that a mass gathering site for an event necessarily entails that the physical space occupied is small, acting to compact crowds. The reverse of this proposition is more suitable, adopting a model where only large spaces are used, allowing people to safely disperse, including spill-out zones to help reduce blocking.

2018 Afghanistan Attacks

Table 2: 2018 April Attacks Occurring in Afghanistan: Gives a snapshot of two recent attacks in Afghanistan, on 22 and 30 April, 2018. These two examples serve to illustrate the ongoing use of in-situ attacks. At the 22 April attack a suicide bomber detonated an IED among more than 120 people who had collected at the door of the voter registration center in Kabul. A photograph showing the aftermath of the attack indicates remains spread along the footpath alongside a substantial brick, concrete and stone-faced wall for the building housing the voter registration center. The blast may have been large, as window are said to have been shattered miles away (Fedschun, 2018). The IED size was a key factor in the high number of fatalities, and other casualties, as was the likely reflection from the building wall, and surrounding street surface. Factors such as concentration of people, waiting to enter the building can also be factored into the high fatality result.

A similar in-situ styled attack later occurred on 30 April that involved a back-to-back bombing near government buildings in Kabul, during the morning rush hour. It is not known what the level of fatalities, or injury resulted from the first bombing, which is known to have been an assailant on a motorcycle, nor how powerful that IED had been. The second explosion, for which there is no information as to the IED composition or size, however shows the use of an in-situ styled attack as it said to have torn through a group of reporters who had gathered at the site of the first incident outside the headquarters of the Ministry of Urban Development. Both attacks show a similar concentration of people within the detonation area caught in-situ, resulting in a very high: in the order of 36.5% (22 April), and 36.7% (30 April) fatalities, even higher than the Table 1: Band Three attacks discussed earlier, the highest of which was 29.8% (31 March, 2002).


Table 2: 2018 April Attacks Occurring in Afghanistan - Source: Author’s analysis of Anti Defamation League/International Policy Institute for Counter-Terrorism (ADL/ICT) database and multiple news reports.

2018 Drone (UAV) Attack on A Parade

The problems posed by the use of drone or unmanned aerial vehicle (UAV) to conventional security had been raised in recent years in regard to sports arenas by several U.S. domestic policing and governmental agencies (Vicinanzo, 2014; Lawson, 2014; Bunker, 2015). UAV use against public events, represents a dynamic option to an attacker, that opens gaps in various security layers (Flaherty, 2018); namely:

“The flight ability of a UAV … may allow it access to venues, such as a sports stadium, where an armed human attacker cannot gain entrance due to security screening protocols.” (Bunker, 2015)

The 4 August, 2018 air explosion of a UAV hovering over Avenida Bolivar, as Bolivarian National Guard stood in ranks listening to an address, parading on the street below, was dramatically captured on film. The guardsmen can be seen breaking ranks and evacuating responding to the explosion above them. This attack emphasises the threat posed from an IED–UAV combination to crowds at events:

“represents an area rather than a point target type of drone attack…. a video link and a simple command—in this instance, that of detonation—can be utilized with a UAV carrying an IED. The intent would be to have the drone fly into a crowd of individuals and detonate among them. This would mimic the effects of a terrorist grenade or IED attack on a grouping of people. An effective use of this form of attack would be to attack crowds in a sports stadium or along a parade route in order to generate panic and create a stampede and/or crowd crush-type situation. Follow-on drones, even if unarmed, could be utilized to create the illusion of a coordinated attack for terror generation purposes.” (Bunker, 2015)

It is currently understood, that the potential IED load for a small UAV will be relatively low (Sullivan, Bunker, and Kuhn, 2018); nevertheless, blocking of parade participants and onlookers in static positions, arguably increases the effect of even a small explosive device as it places a larger number of people in-situ within the lethal detonation zone.

Mitigating the Threat from In-Situ Attacks

A mitigation strategy reducing the threat from in-situ attacks is based on denial of opportunity. A significant part of the mitigation strategy occurs at the pre-event planning stage, such as ensuring parade organisation and its safety is achieved through the reduction in the likely congestion of participants in the marshalling zone. Another key pre-event strategy is reduction of the massing or congestion of event visitors. For instance, some blocking points are outside the actual security exclusion zone set up to protect a mass gathering location. This is an added concern for security of mass gatherings and may see the need to develop crowd management options that operate outside and along the barrier fencing and gate areas to help ease the concentration of people in these places or to get them moving quickly. One possible solution is the use of multiple gate options at regular intervals, much the same as a sports arena with its multiple gate entry points. Mitigating the threat from an in-situ attack primarily focus on human factors, such as the ability to successfully build security management of an event where blocking of people in close confines are reduced significantly, both in the length of time people are left stationary in a place; and the numbers involved. Event staggering to reduce crowd build-up, and provision for regular spill-out points may need to be tested as a future strategy.

Figure 2: Blocking and Dispersion in Mass Gathering Spaces: Illustrate two examples of blocking that can occur within a mass gathering space. These are: (i) congestion of people waiting to enter through a gate; (ii) people placed in fenced paddocks within event spaces. Within the areas between there is a greater dispersion of people. Reducing the option for an in-situ attack to occur directly relates to how events create opportunities for an attacker, such as reducing the common expectation that blocking will occur at certain places, such as at event gates. For instance, it is known that attackers can carry their IED for some time actively looking for the best place to attack, likewise it is the case that attackers have pre-chosen a place that they know at a certain time will have a likely concentration of potential victims. Preventing these types of attack from occurring, requires a high level of security management and allowing dispersion of crowds.


Figure 2: Blocking and Dispersion in Mass Gathering Spaces

Infrastructure minimisation is likely to be a key strategy reducing attacker opportunities. Cluttered infrastructure effectively stops people’s ability to move about. Typically, an in-situ attack is successful because of the number of physical objects in a space, that holds people in position, this can be closely situated furniture, and waist-high fencing. The use of low fencing, such as typically seen at mass spectator events to create trackways for movement in and out of spectator paddocks is increasingly seen as a safety and security feature to allow for crowd management, and emergency access. It may well be necessary to look at cutting the size of the fenced spectator paddocks into smaller ones, as commonly these can kettle more than five hundred people into a single block. In addition to which, adding more walking spaces, and crowd spill-out zones to ease blocking of people into large groups, that offer in inviting target to a would-be attacker.

The most significant part of the mitigation strategy is creating circumstances where people, and CCTV can see a problem. The cluttering of a place with infrastructures and people congestion, occurring over an extended period of time appears to be a key factor in the success of an in-situ attack. The reduction and redesign of lighting, fencing, seating and table options may need to be tested and developed overtime in public spaces, and along streets where mass gathering events are held over the year. This strategy also includes, opening crowds up sufficiently to allow security foot patrols access to wander through a crowd group and maintain visibility.

Postscript: 22 September 2018 Attack on the Iranian Revolutionary Guard Parade

Viewed in terms of TTPs analysis the small selection of examples, used in this discussion paper, illustrate that in-situ attacks may form part of a more widely used tactical methodology that seeks to maximise fatalities by seeking out static concentrations of people as a target attractor. This may even affect the design of the IED used, as it may be the case that a weaker blast yield can be substituted for a stronger one, as in certain circumstances the weaker IED can result in a high number of fatalities where the target group is concentrated in-situ.

In-situ attack methodologies is not restricted to the use of an IED as can be seen in recent events of the 22 September 2018 attack by a party of gunmen on the parade of the Iranian Revolutionary Guard Corps (IRGC), in the southwestern Iranian city of Ahvaz. The attack killed at least 25 people and injured some 70 others, represents approximately 26.3% fatalities (that markedly resembles the band three levels of fatalities recorded in Table 1). In the case of the Ahvaz attack, the attackers used automatic weapons at close range on the parade taking advantage of the fact that the parading soldiers were in tight linear formation, maximising casualties through enfilade. The connection between this event and the use of IEDs on blocked parades is that both tactics are able to maximise the effect of weapons attacking a target grouped together, in close proximity, and constraint (Clarke, Alkhshali, and Hauser, 2018; Joscelyn, 2018; Khalaj, 2018; MEHR, 2018).


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Categories: tactics - doctrine

About the Author(s)

Christopher Flaherty has a Ph.D. in Economic Relations from the University of Melbourne with a focus on networking. Following this, he pursued a career in defence and security research in the Australian Department of Defence. Christopher has been based in London since 2008. A Senior Research Associate of the Terrorism Research Center (TRC), he regularly contributes to its’ current publications. He is also the co-primary author of Body Cavity Bombers: The New Martyrs (iUniverse, 2013). Two essays of his from 2003 and 2010 were reprinted in the TRC book - Fifth Dimensional Operations (iUniverse, 2014). He is the author of Australian Manoeuvrist Strategy (Seaview Press, 1996). Christopher has been an active contributor on security, terrorism early warning, and related international intelligence issues, including tactics, techniques and procedures analysis, published in the TRC report ‘Dangerous Minds’ (2012). He has a long-term involvement in the development of a ‘Scripted Agent Based Microsimulation Project’, at the University of Wollongong (NSW, Australia).