Author: Jonas Feltes

1       Introduction

2       Past Attacks in Liberal Democracies

3       Analysis of decision

4       Anticipation of future attacks



1     Introduction

Since its separation from the al Qaeda network in 2014, the so-called Islamic State of Iraq and the Levant (ISIL) has been increasingly seizing more and more public attention. Despite this global focus on ISIL, al Qaeda still poses a substantial threat to international security and may become more relevant again in light of the recent decline of ISIL’s held territories in Syria and northern Iraq. Furthermore, the weakening of ISIL could also lead to the reunification or at least to an alliance of both groups in the near future. Hence, the aim of this paper to provide a non-exhaustive overview of the weapons that have been used by al Qaeda operatives and affiliates in liberal democracies is topical. Additionally, this overview will be used to further analyse the decision making of these operatives to use a particular weapon for an attack. This analysis is informed by factors like the resources, strategy, and ideology of al Qaeda affiliates in the West that arguably influence this decision process to a large degree. Both the overview of the past weapon use of al Qaeda affiliates as well as the analysis of the reasons for picking certain weapon types will be used in the end of this paper to give an informed, first anticipation regarding the future weapon use and capabilities of the al Qaeda network.

2     Past Attacks in Liberal Democracies

Attacks by the terrorist group al Qaeda can be traced back to the early 1990’s. However, for this brief overview of al Qaeda’s past attacks, only those attacks will be mentioned that happened after 2001, when the group quickly became a great threat to international security. This section will cover both attacks directly orchestrated by al Qaeda affiliates and attacks perpetrated by single actors inspired by the group’s ideology. Additionally, this overview also includes those attacks and unsuccessful plots that cannot be unambiguously attributed to either al Qaeda or other groups (such as ISIL) alone.

2.1  Melee weapons

Melee weapons such as knives, box cutters, axes or other tools count as frequently used weapons in plots and attacks of Al Qaeda against Western democracies. However, in direct comparison to ISIL, al Qaeda does not seem to focuses on these weapon types in particular. As a study of Nesser and Stenersen shows, out of 122 plots and attacks by radical Islamist groups and lone operators in Europe between 1994 and 2013, 10 attacks or plots included knives or other melee weapons. Most of these plots can be attributed to the al Qaeda network or were at least partly inspired by al Qaeda’s ideology.

For example, in 2007 plotted to behead a British soldier with a melee weapon and was reportedly at least inspired by Al Qaeda. Furthermore, Al Qaeda affiliates stabbed the Israeli taxi driver Yafim Weinstein in Nazareth in 2009. Only one year later, the British student Roshonara Choudhry stabbed the politician Stephen Timms with a kitchen knife. The 21 years old attacker was reportedly highly influenced and radicalized  by the sermons of Anwar al-Awlaki, a senior recruiter of Al Qaeda. In 2013 the British Army soldier Lee Rigby was attacked and stabbed close to the Royal Artillery Barracks in London. The perpetrators, Michael Olumide Adebolajo and Michael Oluwatobi Adebowale, hit Rigby with a car and afterwards attacked him with knives and a meat cleaver. At least Adebolajo sympathized and was highly influenced by al Qaeda and the affiliated group Al Shabaab.

In summation, several individuals affiliated with or inspired by Al Qaeda used knives and other melee weapons to conduct attacks in liberal democracies. Almost all of the perpetrators of these attacks conducted targeted assassinations, operated either alone or with maximal two persons and only had very loose – or even no – ties to Al Qaeda itself.

2.2  Firearms

Firearms play a central role in the arsenal of al Qaeda affiliates in liberal democracies. Nesser and Stenersen identified 17 Islamist plots with firearms in Europe between 1994 and 2013 (of which a majority was influenced by al Qaeda) and the Global Terrorism Database (GTD) lists firearms as second most popular weapon of the worldwide network of al Qaeda – with 692 attacks and plots out of a total number of 1909 incidents affiliated with al Qaeda globally.

In Europe, one of the earliest Islamist terrorist attacks with firearms was the assassination of Dutch filmmaker Theo van Gogh in 2004. Van Gogh was murdered by the Islamist Mohammed Bouyeri, who used a HS2000 handgun to assassinate the filmmaker. Al Qaeda has been praising the attack and tried to exchange Bouyeri for Western hostages in North Africa. Another example of al Qaeda inspired terrorism with firearms in Europe is the shooting spree of Arid Uka in 2011. During these attack the 21 years old Kosovan used a semiautomatic handgun to attack members of the US military at Frankfurt International Airport. Uka, who had alledgedly been inspired and radicalized by Jihadist propaganda material[1], killed 2 persons and wounded 2 in Frankfurt. Only one year later, the French jihadist Mohammed Merah started a shooting spree  in southern France with an AK-47 rifle, an UZI submachine gun and several other firearms that lasted from 11 March to 22 March. This spree included the killing of three French paratroopers in Toulouse and Montauban as well as a shooting at a Jewish school in Toulouse with 4 fatalities. After a three day manhunt and a siege in Toulouse, police officers shot Merah on 22 March in his apartment. According to the investigators, Merah’s attacks were inspired by Jihadist groups like al Qaeda. Merah’s suspected ties to the network could never be verified.

The latest attack with ties to al Qaeda in Europe was the attack against the magazine Charlie Hebdo in Paris in early 2015. On 7 January the brothers Chérif and Saïd Kouachi entered the offices of Charlie Hebdo with vz. 58 rifles and other firearms to attack the staff of the satirical magazine. The attack claimed 12 lives and left 11 persons injured. After killing the Kouachi brothers after a siege two days after the attack, the investigators found that at least one of the two brothers, Chérif, had ties to al Qaeda.

Next to European countries, also other liberal democracies fell victim to attacks with firearms executed by al Qaeda affiliates. For example, in 2009 the al Qaeda affiliate Abdulhakim Mujahid Muhammad shot at two US soldiers with an SKS rifle in front of a recruiting office in Little Rock, Arkansas and killed one of them. Furthermore, Nidal Hasan, the perpetrator of the Fort Hood shooting in 2009 that killed 13 US soldiers, can be characterized as close to al Qaeda’s ideology, since he was in contact with Anwar al-Awlaki. After the attack, al-Awlaki praised Hasan’s attack. Furthermore, the magazine Inspire of al Qaeda in the Arabian Peninsula (AQAP) applauded the attack and used Hasan as an example of “Open Source Jihad”.

2.3  Explosives

Improvised explosive devices are by far the most popular weapon in the arsenal of al Qaeda. Out of the 1909 attacks of al Qaeda affiliates listed in the GTD, 1218 attacks were executed with explosives devices. Furthermore, Nesser and Stenersen showed that out of the 133 Jihadi attacks and plots in Europe between 1994 and 2013, 79 plots and attacks were planned or performed with IED’s.

In Europe the two most lethal attacks of al Qaeda affiliates, the Madrid train bombing (2004) and the London 7/7 bombings (2005), were executed with IED’s. In Madrid, a local terrorist cell detonated 7 IED’s on four different commuter trains close to Atocha train station and killed 191 persons as well as injured another 2,050. Shortly after the deadliest terrorist incident in the history of Spain, al Qaeda claimed responsibility for the attack.[2] Investigators found that the cell used the industrial mining explosive Goma-2 as main charge of the IED’s. Goma-2 consists of 60 to 70 percent of ammonium nitrate mixed with ethylene glycol dinitrate. Only one year after the attack in Spain, an al Qaeda affiliated terrorist cell in the United Kingdom executed an attack against public transportation in London. During the attack Hasib Hussain, Mohammad Sidique Khan, Germaine Lindsay, and Shehzad Tanweer detonated four improvised explosives devices on three different Underground trains as well as on a bus in Tavistock Square and killed 56 persons including themselves. The IED’s used for the attack were reportedly made of TATP, HMTD, and a mixture from hydrogen peroxide and black pepper. Furthermore, small scale explosive attacks such as the bombings in Stockholm in 2011 are believed to be at least inspired by al Qaeda: in this attack, Taimour Abdulwahab al-Abdaly detonated a car bomb consisting of petroleum gas bottles that wounded one person and pipe bomb that killed himself. Moreover, in 2015 an al Qaeda affiliate in Oberursel (Germany) plotted to detonate an IED at a local bike race event, but was arrested before the planned attack, since he raised the attention of the security agencies by buying large amounts of hydrogen peroxide at a hardware store.

In the USA, several plots and unsuccessful IED attacks took place that can be traced back to al Qaeda. For example, the al Qaeda affiliate Richard Reid attempted to detonate an IED on a passenger aircraft flying from Paris to Miami on December 22, 2001. However, the IED that mainly consisted of PETN and was hidden in Reid’s shoe failed to detonate and Reid was arrested. Furthermore, the al Qaeda network and specifically Anwar al-Awlaki was suspected to be one of the masterminds behind the so called Cargo planes bomb plot from 2009. During these plots, al Qaeda affiliates attempted to detonate two IED’s containing PETN on board of two different passenger aircrafts flying from Yemen to airports in the US. However, the IED’s that were hidden in printer cartridges in packages were discovered and successfully defused in Leicestershire (England) and Dubai. In December of the same year, Umar Farouk Abdulmutallab attempted to detonate an IED on a passenger aircraft on its way from Amsterdam to Detroit. However, the IED containing PETN and TATP malfunctioned and Abdulmutallab was arrested. Al Qaeda in the Arabian Peninsula (AQAP) claimed responsibility for this attack.

The latest case of explosive terrorism that was inspired by al Qaeda was the bombing of New York City and New Jersey in 2016 that wounded 35 persons. During this attack Ahmad Khan Rahami, who reportedly was radicalized by speeches of Osama Bin Laden and Anwar al-Awlaki, detonated a pipe bomb in Seaside Park (New Jersey) as well as a pressure cooker IED in Chelsea (Manhattan). Additional IED’s were found in both New York City and New Jersey, but were either successfully defused or did not manage to injure anyone. Reportedly, Rahimi used HMTD and ammonium nitrate as main charge for the IED’s and built some of his IED’s according to manuals published in Inspire that repeatedly provided small cells and lone operator with the explicit knowledge to manufacture IED’s as part of the “open source jihad”.[3]

2.4  Ramming attacks

Vehicle based attacks do not seem to be a frequent tactic of al Qaeda operatives. However, one of the very few al Qaeda attacks with vehicles used as weapons was the most devastating terrorist attack in the twenty first century so far: the attacks on 11 September 2001. During this infamous attack, multiple al Qaeda operatives hijacked four passenger aircrafts and steered two of them into the World Trade Centre in New York City and one additional aircraft into the Pentagon building in Arlington that is home to the US Department of Defense. The fourth hijacked aircraft crashed close to Shanksville, Pennsylvania, while reportedly being on its way to the Capitol in Washington DC. 2,996 persons lost their lives during these attacks .

Apart from the devastating events on 11 September, al Qaeda operatives and single actors inspired by al Qaeda do not seem to prefer vehicles as weapons. Apart from the assassination of Lee Rigby, where the perpetrators ran Rigby over before stabbing him, ramming attacks connected to or inspired by al Qaeda are almost entirely absent in Western democracies. However, in general the group itself does not seem to be opposed to the use of vehicles like cars and trucks as weapons. For example, the magazine Inspire called for lone operator ramming attacks in 2010 and even suggested to attach blades to vehicles to create “ultimate mowing machine[s]”(op. cit. Nesser & Stenersen 2014, p.19).

3     Analysis of decision

As shown in the overview above, groups and lone operators affiliated with or inspired by al Qaeda have been using a variety of different weapons for attacks in liberal democracies. In particular, IED’s seem to be the most prevalent weapons in connection to al Qaeda. Vehicle based attacks as well as attacks with knives seem less common in comparison to, for example, ISIL operatives. CBRN weapons have not yet been used successfully by al Qaeda affiliates in liberal democracies.

These choices of weapons made by the respective cells and operators are partly influenced by the general strategy and setup al Qaeda is pursuing in liberal democracies. Several researchers have shown that this strategy changed after the attacks on 11 September 2001. While these attacks were planned in a top down approach by the leadership of al Qaeda and in constant communication with cells and operatives in the West, more recent attacks seem to suggest a contrary trend. After 11 September, most high profile attacks of cells affiliated with or inspired by al Qaeda in Europe and North America showed only a minimal or even no involvement of the al Qaeda leadership in the planning and execution of the attacks. Two examples of this more passive role of the al Qaeda core are the attacks on London and Madrid public transport in 2004 and 2005. Researchers like Christina Hellmich even argue that the whole idea of al Qaeda as a structured network with an influential leadership is inaccurate in general, but should be seen as a loose network with a certain ideology as common core that allows for franchise style cells and subgroups.

Based on these observations it seems that the leadership of the group has been increasingly pursuing the strategy of attacks by autonomous cells and small groups in liberal democracies that require no or only minimal involvement of the core group. One advantage of such a strategy is that this absence of constant communication with high level al Qaeda members make plots less detectable by security agencies. Furthermore, the minimal involvement of the core of al Qaeda in the plots preserves the resources of the core. This hypothesis can be supported by the group’s own communication tool Inspire that explicitly called for “open source jihad” – small scale attacks and even lone wolf terrorist activities in the West. However, in contrast to ISIL, lone operators inspired by al Qaeda seemed to focus on target assassination rather than on random attacks against soft targets. Of course, there are exceptions to this trend towards small scale attacks observable. For example, the unsuccessful cargo bomb plot in 2010 was allegedly planned and executed by core members of AQAP including al-Awlaki and the group’s leading IED manufacturer Ibrahim al-Asiri.

The general change in strategy influences the weapon choices of al Qaeda affiliates in liberal democracies with regard to the resources that either have to be acquired by the cells themselves or that are – at least to a certain degree – provided by the al Qaeda network. First of all, the network does not seem to be substantially engaged in providing financial resources to cells planning and executing attacks in Europe and North America. Researchers like Juan Miguel del Cid Gómez show that most of the al Qaeda affiliated groups in the West – including the cells in Madrid and London – financed their respective attacks autonomously by means of acquiring funds from legal and illegal sources instead of relying on money from al Qaeda senior staff. Furthermore, as seen above the planning of the attacks in Europe and other liberal democracies mostly relies upon the respective cells themselves which means that the operational space of those cells is strictly limited to safe houses and disguised communication.

However, although the core network of al Qaeda seems to be almost entirely absent in the financial support of many plots in liberal democracies, the network can be seen as vital source of expertise and ideological guidance for local cells. For example, according to the alleged al Qaeda operative Rashid Rauf, two of the perpetrators of the London attacks, Mohammad Sidique Khanand Shehzad Tanweer, travelled to Pakistan to attend a training program in IED manufacturing that was affiliated with al Qaeda operatives in the region. A journalistic account of Rauf’s remarks reads:

“Rauf wrote that Haji arranged for a trainer called Marwan Suri to provide bomb-making training using hexamine peroxide detonators and hydrogen peroxide. Siddique Khan and Tanweer test-detonated a 300-gram hydrogen peroxide mixture in the tribal areas. ‘Siddique was always saying to me I hope these mixtures are as good as you say they are. After he tested the mixtures he was very happy’, Rauf wrote.”.

This quote clearly shows that Tanweer and Khan acquired the tacit knowledge to assemble and use peroxide based explosives with the help of the wider network of al Qaeda. With the careful supervision of al Qaeda IED experts, Khan even performed test detonations and, thereby, gained the expertise that was necessary to prepare the attack in London. However, it is important to notice that, due to its strategic change, the group started to discourage Western lone operators and cells to seek training abroad.

In addition to supporting local cells in the acquisition of practical expertise (tacit knowledge), the network is also providing the necessary explicit knowledge to cells and lone operators overseas. For example, the AQAP magazine Inspire repeatedly published IED manufacturing manuals. Furthermore, Anne Stenersen argues that al Qaeda affiliates or at least sympathizers with the group set up “virtual training camps” and e-learning resources to train lone operators and small cells in Europe. In addition to these al Qaeda affiliated source of expertise, European cells appear to get explicit knowledge from more general sources not specific to al Qaeda such as online-manuals in the Al-Aqsa Encyclopaedia as researcher Akil N. Awan suggests. Concerning this, he writes: „[T]he manufacture of acetone peroxide, the material allegedly used in both the 7 July and 21 July attacks, is given a comprehensive treatment in the online Al-Aqsa Encyclopaedia, available on a number of jihadi forums“.

A last, but maybe most crucial resource that al Qaeda is providing to their affiliates and sympathizers in liberal democracies is ideological support and guidance. With preachers and affiliates like Anwar al-Awlaki, the group has key ideologists of the jihadi movement that manage to inspire a large amount of attacks in the West – even after his death in 2010 this proves to be true. Only a few examples of al-Awlaki “inspirations” are listed above in the section on al Qaeda’s past attacks.

The predominant strategy of semi-autonomous cells with up to ten members as well as the provision of both tacit and explicit knowledge from the broader network of al Qaeda enables al Qaeda affiliated or inspired groups in liberal democracies to choose from a fairly broad range of weaponry. Simple IED technologies and firearms seem to be the weapons of choice for these groups. The limited financial resources of these cell obviously restrict the weapon choices of the groups, but still allow for high impact attacks as, for example, seen in London in 2005. Here, especially homemade explosive such as TATP and HMTD do not require vast financial resources and their components are readily available on the free market. Reportedly, Khan’s and Tanweer’s cell only spend approximately 8,000 GBP for the attack on public transport systems in London. Although al Qaeda attempted to shift its strategy in liberal democracies towards a lone operator model and actively encouraged individual attacks with low tech weaponry such as vehicles, this influencing of grass root decision making did not work entirely – not least because of the rise of ISIL and the success of its ideology among European jihadists.

At the other end of the weapon technology scale, the core network of al Qaeda reportedly formulated strong interest in acquiring and using weapons of mass destruction and CBRN technologies against the “far enemy” in the West. As early as in 1998 former al Qaeda leader Osama Bin Laden explicitly stressed that the use of WMD’s against al Qaeda’s enemies would be in accordance with the group’s ideology and should, in fact, be seen as “a religious duty” (op. cit. Ackerman & Pereira 2014, p.27). However, to this date the group and its broader network never successfully used any of the CBRN technologies in liberal democracies. This absence of CBRN in the arsenal of al Qaeda can be seen as a result of both the group’s focus on the “far enemy” in the West and the limitation of resources resulting from this focus. As shown in this section, al Qaeda affiliates in Western democracies mostly rely on financial resources and operational space acquired by the cells themselves in the West. However, while this may not impose large restrictions on the use of conventional weaponry, the successful, large scale use of CBRN weaponry would not only require vast expertise, but especially a safe and broad operational space (e.g. a lab or even a factory) as well as vast financial resources. However, the provision of both of these resources by core groups of the al Qaeda network such as AQAP (which might possess substantial financial resources in Jemen and the broader region) would increase the risk of arrest for European cells dramatically. Furthermore, the acquisition of CBRN materials such as pathogens or radiological agents would even more increase this risk of detection.

4     Anticipation of future attacks

Both the overview of the past attacks of al Qaeda affiliates in Western democracies as well as the analysis of the weapon use during these attacks allow to anticipate general trends in the future weapon use of the group in liberal democracies. However, to present a realistic anticipation, one has to comment on one additional, important development with regard to al Qaeda’s presence in liberal democracies – namely the recent rise of ISIL.

Although the early group of Jamaat al-Tawhid wa-l-Jihad with its leader Abu Musab al-Zarqawi pledged alliance (baya) to al Qaeda in the 1990’s and acted under the name al Qaeda in Iraq (AQI) until 2006, the group renamed itself into ISI and then ISIL (or ISIS) with its current leader Abu Bakr al-Baghdadi and finally broke with the al Qaeda network in early 2014. From 2014 on, both groups have not only been rejecting the legitimacy of the respective other group, but have been actively fighting each other. Parts of these hostilities between al Qaeda and ISIL can be traced back to a tactical dissent between the al Qaeda leadership and al-Zarqawi: According to (back then) senior AQ-affiliate Ayman al-Zawahiri, al-Zarqawi depleted support of al Qaeda in the region by conducting extremely violent and indiscriminate attacks against civilians including Sunnis and Muslims in general.

However, currently and especially due to the developments during the civil war in Syria, not al Qaeda but ISIL seems to be the leading terrorist organization and, accordingly, seems to be either supporting or inspiring most recent terrorist attacks in Europe, the USA and other liberal democracies. One effect of this change is that the local Jihadi cultures especially in Europe seemed to have changed their ideological affiliation and support from al Qaeda to ISIL. As Nesser and Stenersen show, many of the recent attacks affiliates with ISIL can be traced back to the same, loose networks, groups, and individuals that once supported al Qaeda in Europe. Thus, in general it seems more likely to expect further attacks of ISIL affiliates and especially attacks of lone operators inspired by ISIL rather plots affiliated with al Qaeda.

However, this status quo might change. Although there is only anecdotal evidence to assume an increase of al Qaeda related attacks in liberal democracies in the near future, one could think of two scenarios in which al Qaeda might decide to increase their engagement in the West. These scenarios would also strongly influence the future weapon choices of the group:

The first possible scenarios would be the attempt of al Qaeda to regain relevance in the armed struggle against the “far enemy”. One strategy for the group to regain the attention and sympathy of the Jihadi communities in Western democracies would be to plan and execute a major attack in the West that visualizes the capabilities, strength, and commitment of the group. However, to draw current jihadists away from ISIL, this strike would have to be an unprecedented attack with either novel tactics and weaponry or with exceptionally high numbers of fatalities. Here, CBRN technologies could be of interest to the group. Yet due to al Qaeda’s limited resources in the West, it seems unlikely that the group would be capable of acquiring and operating complex biological agents or even nuclear weapons. Furthermore, due to ineffective attempts to use chemical weapons in Iraq in the past, al Qaeda might not be interested in pursuing the path of chemical warfare either to regain credibility.

Thus, it seems more realistic to assume that al Qaeda cells in Europe will not use CBRN technologies as main weapons, but as supplementary, psychological means to regain attention. For example, a cell could try to execute coordinated attacks with conventional IED’s in major European cities, since al Qaeda’s past attacks show that this weapon technology seems a good choice based on the group’s structure, resources, and tactics in liberal democracies. In addition to these conventional IED’s al Qaeda cells could possibly attempt to acquire precursors for RDD’s to accompany these IED attacks as, in fact, not more lethal, but psychologically harming supplement. Such an attack could have the additional, worrying effect of starting an arms race between al Qaeda and ISIL in the West with improvised CR devices as additional weapon technologies. However, such an arms race would be strictly limited by the available resources of both groups in liberal democracies.

A second possible scenario in which al Qaeda would regain its attack capabilities in Europe and North America would be a thinkable consequence of the international fight against ISIL in Syria and Iraq. With the ongoing offences of Iraqi state forces and Kurdish troops against the ISIL strongholds in Mosul and Raqqa, the group constantly loses operational space and resources and might very well be decapitated during the ongoing battles, since it seems reasonable to assume that a large amount of the ISIL leadership is located in both Raqqa and Mosul. However, of course this weakening of ISIL in Syria and Iraq will not prevent sympathizers and affiliates of the group from planning and executing attacks in liberal democracies. Rather, one could assume that the weakening of the ISIL core will increase the risk of attacks in the West. However, the decapitation of the group in Syria and Iraq could lead to improving relations and even to discussions about reunification with al Qaeda. To remain relevant and to consolidate power, both groups might be interested in remerging with each other once one of the group’s is factually leaderless. According to Iraqi vice president Ayad Allawi, both networks are currently discussing stronger relations and even reunification.

The merging of ISIL and al Qaeda would create a highly resourceful, global network that might be capable of planning and executing high profile attacks in the West. Due to the variety of weapon expertise in both al Qaeda and especially ISIL, attacks with novel weapon innovations such as hobby drones or RDD’s might be possible, but such a merged network would seem more likely to further pursue the tactics of large amounts of low tech attacks of sympathizers, since these attacks seem to be effective for ISIL at the moment.


[1] Although Arid’s attack could never be identified as linked to or even inspired by al Qaeda specifically, it was included into this list, since the al Qaeda magazine Inspire used Arid Uka and his attack for propaganda purposes.

[2] Despite this claim, it is still unclear to what extent the Spanish cell communicated directly with core al Qaeda members.

[3] Although not specifically inspired by al Qaeda, the perpetrators of the attacks against participants of the Boston marathon used bomb manufacturing manuals in Inspire as well to assemble their IED’s.