Author: Jonas Feltes

1       Introduction

2       Past attacks in Western democracies

3       Analysis of decision

4       Anticipation of future attacks



1     Introduction

Unlike symmetrical warfare, the strategy of terrorism allows for the use of a wide range of conventional and unconventional weaponry. Thus, terrorist groups and lone operators have been using not only firearms or explosives, but also biological agents, vehicles or even drones to commit attacks. This paper presents a short overview of the weaponry that has been used by affiliates of the so-called Islamic State (ISIL). Although designed as a non-exhaustive overview, this paper will also give insights into the decision making of the respective groups to use specific weapon types. Here, group factors like resources, strategic aims, ideology, and preferred tactics will influence this analysis of the weapon choices of ISIL affiliates. Finally, both the overview and the analysis will be used to formulate first anticipation of the future weapon use of the group.

2     Past attacks in Western democracies

For the past three years, the self-proclaimed Islamic State (ISIL) has been the most active terrorist organization in the European Union as well as in the United States of America, Australia, and Great Britain. In the following section attacks and plots of ISIL affiliates or single actors inspired by ISIL will be summarized by means of the weapons that were used in these incidents. This summary does not only include a non-exhaustive amount of successful attacks, but also covers relevant unsuccessful plots. However, since weapons involved in successful attacks seem more likely to be used in future attacks, the present study favours those attacks that led to – from ISIL’s perspective – successful outcomes.

2.1  Melee weapons

Melee weapons such as knives, axes, machetes or meat cleavers are popular weapons among individuals affiliated with or inspired by ISIL. The perpetrator of the Endeavour Hill attack (Australia in 2014), the attacker in Magnanville (France in 2016), who killed 2 persons, as well as the two perpetrators of the attack in a church in Normandy (France in 2016) used knives as weapons. Furthermore, knives were used in the attacks in Minto (Australia in 2016), in Hannover (Germany in 2016), at Ohio State University (USA in 2016)[1], at the Louvre museum in Paris (France in 2017) and in London (Great Britain in 2017). In London and Ohio, the knife attacks were accompanied by vehicle based attacks. In one additional attack in Würzburg (Germany in 2016), an axe was used as a weapon and the perpetrator of another incident in Paris (France in 2016) used a meat cleaver as a weapon. Notably, all perpetrators of the above mentioned incidents could be identified as single actor terrorists with the exception of the Normandy church attack.

2.2  Firearms

Firearms can be identified as a second, major weapon type that is favoured by ISIL operators. For example, the attack against the Jewish Museum in Brussels (Belgium in 2014) during which four persons lost their lives was conducted with the assault rifle AK-47 Kalashnikov. Only four months later, a lone operator inspired by ISIL entered a coffee shop in Sydney with a shotgun as well as a handgun and took several persons hostage of which 3 persons including the perpetrator died. In February 2015, a series of shootings took place at a cultural centre and a Synagogue in Copenhagen. The perpetrator of these attacks, Omar Abdel Hamid El-Hussein, was inspired by ISIL and used a M/95 assault rifle as well as handguns during the attack. The most severe attack of ISIL against a Western state was committed in Paris (France in 2015) and took 137 lives. During this attack, an ISIL cell around Abdelhamid Abaaoud detonated several IEDs and started killing sprees with AK-47 assault rifles in restaurants and a night club.

Semi-automatic rifles and other guns were also used by the ISIL inspired perpetrators of the shooting in San Bernardino (USA in 2015) and Tel Aviv (Israel in 2016) as well as by Omar Mateen who shot 50 persons in a nightclub in Orlando (USA in 2016). The latest attack with connection to ISIL was the shooting at Champs-Élysées (France in 2017) during which the lone operator Karim Cheurfi shot at three police officers and killed one of them with an AK 47 rifle. Other than in case of knife attacks, attacks with firearms were executed by both lone operators and organized groups in cell size that were in direct contact to ISIL in Syria and Iraq.

2.3  Explosive devices

Next to melee weapons and firearms, also a variety of explosive devices were used by terrorists affiliated with or inspired by ISIL. However, in a majority of these attacks, improvised explosives devices (IEDs) were used in combination with firearms. For example, during the attack in Paris in November 2015, the cell around Abaaoud did not only use assault rifles, but also detonated three homemade suicide vests containing triacetone triperoxide (TATP). However, the vast majority of casualties during this attack were produced by firearms. Furthermore, the ISIL inspired couple that executed the attack in San Bernardino attempted to detonate three IEDs that were connected with Christmas decoration lights. In journalistic sources these IEDs were portrayed as “pipe bombs” based on manufacturing manuals in the al Qaeda magazine Inspire.[2] In March 2016, the cell around Abaaoud committed a second attack in which they used TATP based explosives as a main weapon that killed 35 people at Brussels International Airport and at a subway station.

Although especially the two IED attacks in Europe were committed by an organized cell with tacit knowledge[3] in IED manufacturing, also lone operators with ties to ISIL managed to commit attacks with explosives. For example, in July 2016 the Syrian refugee Mohammad Daleel detonated a TATP based suicide vest in Ansbach (Germany) that killed himself and wounded 15 other persons. . Finally, the ISIL affiliate Salman Ramadan Abedi detonated an IED containing TATP at a pop concert in Manchester on 22 May 2017. The attack killed 23 persons and wounded 250.

2.4  Ramming attacks

The most recent development in the weapon use of ISIL in Europe and other Western nations may be the use of vehicles to commit attacks. Although certainly a novel addition to the tactical repertoire of ISIL, the concept of ramming attack itself is not new, but has been used by Hamas in the theatre of the Israel-Palestine conflict for at least a decade.[4]

The first significant attack that was committed with a vehicle in Western countries was executed by the lone operator Mohamed Lahouaiej-Bouhlel, who drove a Renault Midlun cargo truck into a crowd of people celebrating the Bastille Day on the Promenade des Anglais in Nice (France in 2016). Lahouaiej-Bouhlel killed 86 people and injured 434 others. In the USA, the perpetrator of the Ohio State University stabbing (USA in 2016) additionally used a Honda Civic to deliberately run several students over. In December 2016, the ISIL affiliate Anis Amri steered a Scania R 450 truck into a Christmas market in Berlin (Germany) and killed 12 people as well as wounded 56 others. Most recently the perpetrator of the stabbing incident in London (UK in 2017) used a Hyundai Tucson to deliberately target pedestrians on Westminster bridge. At the time of writing the latest incident involving a vehicle as a weapon was the attack in Stockholm (Sweden in 2017) during which the lone operator Rakhmat Akilov drove a hijacked brewery truck into a shopping street and killed 5 pedestrians. In the aftermath of this attack it was reported that Rakhmat Akilov was inspired by and had contact with ISIL. In March and June 2017, two separate ramming attacks that also included stabbing occurred at the Westminster Bridge and the London bridge in London (UK). The attacks resulted in 6 and 8 fatalities respectively and both perpetrators were identified as being at least inspired by ISIL. One of the latest ramming attacks with connection to ISIL took place in Barcelona (Spain) on 17 August, 2017. During this attack, a small Jihadi cell killed 13 persons and wounded 130 more by steering a van into a popular pedestrian area. The ISIL affiliated news agency Amaq praised the attack and portrayed the perpetrators as soldiers of the network.

As one of the most novel tactics of ISIL in Western countries, the vehicle as a weapon seems to be especially popular among ISIL inspired lone operators with either loose or no contact to the group.

2.5  The arsenal of ISIL in Syria and Iraq

In contrast to the weapons used by ISIL affiliates in Western democracies, the group’s arsenal in its held territories can be characterized as both diverse and sophisticated. According to the most recent report by Amnesty International, the group possesses vast amounts of military weaponry in their strongholds in Syria and Iraq. Yet since ISIL’s areas of influence in Syria and Iraq have been shrinking dramatically within the last months, some of the below listed weapon types may not be at ISIL’s disposal anymore.

The researchers involved in the report concluded that ISIL uses a variety of firearms in its territory including especially AK-47 Kalashnikov rifles, but also M16 rifles and Walther P99 handguns. Furthermore, ISIL fighters in this region are using anti-material rifles including Sayyad-2 AM50 and M99 rifles as well as other light military weapons such as ZU-23-2 automatic cannons. It is noteworthy that ISIL is not only using these weapons in combat operations against Syrian and Iraqi state forces, but also commits acts of terrorism and other war crimes against the civilian population. For example, according to a confidential source, ISIL operatives executed groups of prisoners with a ZU-32-2 cannon in one instance. In addition to this arsenal of firearms, it was also reported that ISIL possesses RPG’s such as OG-7V and SPG models as well as TOW systems and Kornet ATGW systems that can be used against enemy armoured vehicles and tanks. Furthermore, ISIL operatives have been using several types of mortars as well as man-portable air defence systems (MANPADS) such as Chinese FN-6 systems in combat situations. During combat, especially attacks with mortars were conducted indiscriminately and, thereby, killed numerous civilians.

However, ISIL does not only possess large amounts of man-operated light weaponry, but also managed to acquire large quantities of armoured fighting vehicles in Syria and Iraq. For example, the Amnesty International analysts found evidence of Russian T-54, T-55, and T-62 tanks as well as US M1A1M “Abrams” tanks that were captured or otherwise acquired by ISIL in the region. However, at least in case of the M1A1M tanks, no sources for the involvement of these vehicles in combat situations were found. Apart from these tanks, ISIL reportedly possesses Russian BMP-1 and MT-LB infantry fighting vehicles as well as US M113A2 and M1117 personnel carriers and HM-MWV “Humvee” vehicles.

This extensive arsenal raises questions concerning the sources of ISIL weaponry in the region. With regard to these questions, the Amnesty International report states that the group acquires its weapons through a variety of channels including illicit arms trade and especially via capturing and looting existing military weaponry in the region. For example, the investigators concluded that ISIL operatives managed to loot 41 Humvees and four M1A1M tanks in one instance in Mosul in 2014. In other instance in the year 2015, ISIL fighters captured more than 100 armoured fighting vehicles in Ramadi as well as a fighter aircraft and even several combat helicopters from an airbase in al-Raqqa. However, it is reasonable to assume that at least the aerial vehicles were never used by ISIL, but destroyed or disassembled. In summation, due to the past and present military presence of the US military in Iraq and the increased presence of military vehicles and weaponry of regional forces due to the Syrian civil war, ISIL potentially has vast amounts of advanced weaponry at its disposal.

However, apart from these conventional firearms and military weapons, ISIL also repeatedly used both improvised weaponry as well as unconventional and banned weapons in Syria and Iraq. For example, ISIL has been manufacturing large amounts of IEDs and repeatedly used those technologies in both combat situations with Syrian and Iraqi forces as well as in suicide bombings and terrorist attacks against the civilian population in the region. Reportedly, these IED technologies have been manufactured in dedicated explosive “factories” and workshops and show high degrees of sophistication. The explosive charges for these devices were assumable acquired by both looting military stocks and collecting dual-use materials such as ammonium nitrate. A popular example of the sophistication of ISIL made IEDs is the repeated use of off-the-shelf hobby drones to deliver explosive devices in the battle against Iraqi state forces in Mosul and near Raqqa. Furthermore, ISIL is accused of equipping IEDs with poison coated metal balls as shrapnel filling. In addition to IED innovations, ISIL has also been using water as a weapon in the region. Specifically, the group repeatedly denied villages the supply with water in their territories and flooded other villages by using captured dams in Syria and Iraq. Finally, ISIL affiliates reportedly poisoned or soiled drinking water in cities like Raqqa, Aleppo, and even Baghdad.

Finally, both Amnesty International as well as the UN Organization for the Prohibition of Chemical Weapons (OPCW) report that ISIL has been using banned weapons of war in the theatre of the Syrian civil war. Next to allegations that ISIL possesses and used cluster munitions from China in at least one instance, one of the most popular findings of the involved analysts was the use of chemical warfare by the group in Syria. According to the OPCW report, ISIL operatives used chemical warheads in at least one instance on 2015: On 21 August, the group launched approximately 50 artillery shells several of which were filled with sulphur mustard in Marea (Syria) and caused at least one civilian death. In the aftermath of this attack  up to 80 people from the village sought medical attention. While the OPCW maintained that there was insufficient information available to identify the source of the chemical agent in this instance, the report suggested that the agent might have been manufactured by the group. Furthermore, some authors suggest that ISIL might engage in manufacturing improvised chemical weapons as well as may have acquired chemical warfare agents from the stockpiles of the Syrian government.

As for the CBRN capabilities of ISIL in the region in general, it is reasonable to assume that the group is not only interested and, in fact, engaged in attacks with chemical warfare, but might be both capable and motivated to manufacture rudimentary radiological dispersal devices (RDDs) as well. However, both ISIL’s improvised or small scale chemical weapons and potential RDDs do not seem effective weapons for offensives against enemy combatants, since the group lacks appropriate protective equipment and has a vital interest in extending its area of influence. Furthermore, at least RDDs have proven to be largely ineffective aside from the damage caused by their detonation. Hence, ISIL might use both chemical and radiological weapons either as deterrent to slow down enemy offenses or as tools of terror against the civilian population that transport a large psychological effect due to the (perceived) contamination of public areas and persons. Biological as well as nuclear weapons have not been used by ISIL yet and seem less likely to be acquired by the group. The following section will give reasons for this.


3     Analysis of decision

As summarized above, terrorists with ties to or inspired by ISIL are using different classes of weapons to commit attacks in Western liberal democracies. Furthermore, it already has been stated shortly that certain types of weapons (melee and knives) seem to be more frequent among single actor terrorists, whereas others (e.g. IEDs) are being mainly used by groups and cells. Possible reasons for these weapon choices will be analysed in the following.

First of all, one has to distinguish between the capabilities of ISIL in its held territories in Syria and Iraq in contrast to the group’s resources in Western liberal democracies. ISIL in, for example, Mosul and Raqqa possesses a vast amount of financial resources, tacit and explicit knowledge in weapon manufacturing, and owns a large operational space. These factors allow the group to innovate new tactics and weapon technologies. In addition to novel innovations, the group also possesses vast amounts of military weapons that were seized, looted, or stolen from Syrian and Iraqi state forces. Here, the availability of these technologies can be seen as a major influencing factor for the use of these weapons. Furthermore, the strategy of the group in Syria and Iraq is mainly focused on warfare and active combat situations against Syrian and Iraqi state forces and forces of the Anti-IS coalition. Thus, the group is especially interested in acquiring and innovating weapon technologies for open combat. As seen above, the group is also using these sophisticated technologies as tools of terror against civilians.

However, even the extraordinarily extensive resources of ISIL in Syria and Iraq cannot be considered extensive enough for certain, highly advanced, weapon technologies. As shown above, the group acquired but never used certain tanks and military aerial vehicles, since it seems to lack the expertise and human resources to operate these systems. Furthermore, recent studies suggested that nuclear weapon technologies as well as sophisticated biological weapons seem to be out of reach for the group, since the financial resources and especially the expertise of the group is not extensive enough to successfully acquire and deploy these technologies.

The vast resources of the group in its held territories are far from comparable to the resources of ISIL operatives in Europe. Here, the group is facing an entirely different environment. There are only minimal organizational structures of ISIL visible in form of small cells such as the group around Abaaoud. These cells only possess limited financial resources and rely upon very few individuals who are experienced in IED manufacturing and tactics (such as Abaaoud himself, who gained that experience in Syria). Partly, these loose structures of ISIL in Western countries are based on a strategic decision of the group to avoid detection by security agencies. However, in return that also means that ISIL operatives in Western democracies cannot rely upon the vast (but recently shrinking) resources of the group in Syria and Iraq. While a certain amount of expertise can be transferred via online manuals and returning foreign fighters, financial matters rely almost entirely upon the financial situation of the operatives themselves except maybe several thousand euros in cash that the group provided to returning fighters from Syria. In case of lone operators, these resources may be even more limited, often only including legal income as well as explicit knowledge about tactics and weaponry from the internet. Obviously, the operational space of these operators and cells are strictly limited as well.

These limited resources in relation to the risk of arrest in Western democracies interact with the strategic aims and tactical objectives of ISIL in these countries. Rather than pursuing a strategy of holding and securing territory, ISIL aims at disrupting civil order and spreading fear on a low level in Western democracies. For these strategical aims, open warfare with advanced and innovative weaponry as realized in Syria and Iraq is neither a suitable nor an effective measure. Instead, the group is focussing on a mixture of few medium scale attacks (Paris in 2015, Brussels in 2016) committed by small cells and especially a large amount of low scale attack by sympathisers and single actor terrorists in constant intervals. With these tactics, of which the latter one may not be exactly controllable but also not detectable beforehand, ISIL aims at seeding an environment of fear and consequently disruption in European and other Western countries. One core element in this strategy is the attacking of random, soft targets such as shopping areas, festivals, or public transport.

However, these tactics coupled with the limited resources of the group in Western countries only allow for a limited range of weapon technologies: Cells like the group around Abaaoud may be the most resourceful ISIL agents in this region and, hence, could opt for a fairly wide range of weaponry including the use of IEDs that demands a certain amount of financial resources as well as a vast amount of expertise in the sense of both explicit and tacit knowledge. Furthermore, the cell also managed to acquire AKM assault rifles. However, the planning of the attack as well as the preparation of the IEDs involved a variety of individuals and was both space and time demanding – factors that increased the risk of detection and arrest. In contrast, the majority of lone operators seem to refrain from technologically advanced weaponry and appear to rely upon low-tech solutions such as melee weapons or vehicles. Attacks with these weapons drastically reduce the risk of arrest, since only minor or no preparatory measures are needed. Furthermore, almost no financial resources and very basic expertise is needed to successfully execute an attack that serves the strategical aims (disrupt societies) of ISIL in liberal democracies. Thus, even individuals with very limited resources and no or minimal contact to the group itself can partake in these strategical aims.

Of course, this distinction between relatively resourceful cells on the one and lone operators on the other side with their respective weapon choices is only representing two extremes on a scale that includes many more facets. For example, lone operators may – and indeed did – choose to use more advanced weaponry such as firearms for attacks if these weapons are readily available in their region (e.g. in the USA and in Belgium until 2006) and if their financial resources allow for this. The attack in Orlando or the shooting in the Jewish Museum in Brussels are only two examples of such decision making. Furthermore, due to the vast amount of explicit knowledge on the internet, lone operators with remote guidance and “inspired” individuals may successfully assemble explosive devices. Here, especially peroxide based explosives such as TATP and HMTD (Hexamethylene triperoxide diamine) are popular, since the precursors for these explosives can be purchased on the free market without or with only minor restrictions. However, as the foiled plot in Chemnitz has shown the preparatory measures for an IED attack dramatically increase the risk of arrest – even if only a single actor is involved. Due to this risk, ISIL has been repeatedly calling in its magazine Rumiyah (former Dabiq) for its operatives in the West to use small scale attack with low tech weaponry such as knives or vehicles to avoid arrest and to ensure “success” even with limited expertise and money.

The last influencing factor for weapon choices of ISIL affiliates and sympathizers in Western democracies is the ideological setup of the group. Ideology can determine what kind of weapons may or may not be allowed to be used in attacks, since only a certain set of persons may be justifiable targets for the group. For example, the first generation of the Red Army Faction (RAF) was not primarily interested in acquiring indiscriminate weaponry, since their specific Marxist-Leninist ideology did not allow to target random civilians indiscriminately. However, ISIL as a religious extremist group that could arguably characterized as an apocalyptic cult does not seem to present the same ideological restrictions. Rather, every individual that is not part of the group’s specific interpretation of Islamic religion is a legitimate and potential target and, furthermore, many of its followers perceive the fight of the group as the battle before Judgement Day. This ideology allows for a wide range of weapon technologies including highly indiscriminate CBRN technologies. Thus, the reason why these weapon technologies have not been used in Western democracies so far can rather be found in the discussion concerning resources and risk of arrest above.

However, although not particularly indiscriminate, certain other weapons that have been used by ISIL operatives in Western democracies carry specific ideological value for the group as well. For example, the repeated use of the AK-47 rifle could be interpreted as an attempt to legitimize the group’s attack as justified political struggle, since this specific rifle has gained the status of a symbol of resistance and guerrilla warfare among armed groups around the world.

4     Anticipation of future attacks

Informed by both the summary of the weapons that have already been used in attacks of ISIL and the analysis of the influencing factors that led to the use of these weapons, one can formulate short assumptions about the future use of weapon technologies of ISIL in liberal democracies.

First of all, under the impression of the recent attacks in London, Stockholm, and Paris, one could anticipate that attacks with lone operators as perpetrators will stay one of the main threats to European security in particular. Based on the accounts in Rumiyah, the ISIL command seems to perceive this tactic as especially promising to pursue its strategical aims in the West. Weapon types specific to this tactic are melee weapons, vehicles and a limited range of firearms. These weapons will stay to be of utmost importance to Western counter-terrorism efforts. Proper responses have to be developed to interrupt and stop attacks as they happen, since the minimal (or absent) preparations for these attacks do not seem to allow for detection beforehand. Secondly, cell structures with knowledgeable and slightly resourceful individuals may plan further medium scale attacks in the future. With regard to Europe, researchers like Nesser, Stenersen, and Oftedal anticipate a similar trend. Weaponry specific to ISIL cells include both automatic weaponry and IEDs. At least in the case of the latter technology, an interruption of preparatory measures by security agencies is possible, since time, space, expertise, and materials are needed to assemble these weapons. This allows for detection.

Furthermore, one could assume that the explicit knowledge available on the World Wide Web motivates even small cells to manufacture a wider range of weaponry such as drone based IEDs or even crude chemical or radiological[5] devices. However, these ideologically permitted acquisition of indiscriminate weaponry is harshly restricted by the available financial resources and the operational space of the group as well as by pre-existing tacit knowledge of its members. Furthermore, the preparatory measures for such attacks are not only extremely expensive, but also seem to be easily detectable and, thus, may not be a priority for ISIL in the West – not least because especially chemical agents have to be manufactured shortly before their deployment and cannot be stored for a long period without sophisticated containment technologies.

Although in the past some circumstantial evidence showed the interest of European cells in these advanced technologies[6], it seems more likely that ISIL operatives will use their resources to continue conventional attacks in the near future. However, the increasing experienced based expertise of ISIL operatives in assembling drone based IED’s and chemical weaponry in Syria and Iraq as well as the group’s operational space and resources in this region is a cause for concern that should be treated with a low risk tolerance by Western intelligence agencies – not least because the improbable case of a CBR event in liberal democracies would have dramatic consequences that outweigh probability. For while the physical damage resulting from an RDD might not exceed the damage caused by an IED, the psychological effect of such an attack in the heart of Europe would be extremely disruptive.


[1] In case of the incident at Ohio State University, it is not entirely clear, if the perpetrator was in fact inspired by ISIL or Al Qaeda yet media outlets with ISIL connection characterized them as ISIL affiliates.

[2] Based on descriptions in Inspire, one could assume that the couple used either TATP or ammonium nitrate for the IED manufacturing.

[3] This study distinguishes between tacit and explicit knowledge. While explicit knowledge refers to knowledge from manuals, videos, and other instructional material, tacit knowledge can be characterized as experience based knowledge that is bound to human beings.

[4] One prominent example may be the so called “bulldozer attack” in 2008 during which a lone operator used a front-end loader to attack pedestrians in Jerusalem (McCharthy 2008).

[5] This discussion leaves out biological and nuclear weapons, since an ISIL attack with a nuclear or sophisticated biological weapon in the West seems highly unlikely.

[6] For example, ISIL affiliates in Belgium monitored a nuclear scientist and apparently had an interest in acquiring radiological materials.