Terrorist organizations strategically adapt and evolve their tactics and weaponry in response to shifting contexts and opportunities. These groups have exhibited a growing ability to incorporate emerging technologies and diversify their methods of violence, thereby sustaining a high level of lethality and operational effectiveness on a global scale. According to data from the Global Terrorism Trends and Analysis Center (GTTAC), terrorist attacks in 2024 alone resulted in 18,987 fatalities across 8,612 incidents. The data further reveal that terrorist actors employ a broad spectrum of weapon types, including firearms, explosives, improvised explosive devices (IEDs), incendiary devices, and melee weapons. Between 2018 and 2024, GTTAC recorded 58,898 terrorist incidents worldwide, with firearms being the most frequently used weapon, appearing in 44% of all recorded attacks. Explosives were the second most commonly used, involved in 21% of incidents, followed by IEDs, which accounted for 16%.
Explosives encompass a broad spectrum, ranging from rudimentary IEDs to sophisticated commercial or military-grade explosives. Hand grenades are among the most basic and widely used explosive weapons, which are valued for their portability, ease of concealment, and operational simplicity. Despite their relatively limited blast radius—typically effective within approximately five meters (16 feet) of the detonation point—hand grenades remain a favored choice for terrorist actors due to their accessibility and tactical utility in close-range attacks. Rocket-propelled grenades (RPGs) are highly potent explosive weapons frequently utilized by terrorist organizations, particularly for targeting fortified structures such as bunkers and buildings. These weapons are often integral to complex and coordinated assaults, serving as key components in the tactical arsenals.
Terrorist organizations frequently employ bombs as a primary form of explosive device, with the vast majority being IEDs constructed from commercially available materials. Common components include traditional explosives such as dynamite and trinitrotoluene (TNT). The invention of dynamite—composed of nitroglycerin, sorbents, and stabilizers—marked a turning point in the history of political violence, facilitating the early use of explosives by anarchist and revolutionary movements in 19th-century Russia and Western Europe. By the 20th century, the development and accessibility of plastic explosives significantly broadened the range of IEDs. Notable examples include Semtex, Composite-4 (C-4), and ammonium nitrate–fuel oil (ANFO) explosives.
Semtex, a nitroimine-based plastic explosive, was widely distributed on the international black market and was discovered in significant quantities in Libya following the collapse of Colonel Muammar Gaddafi’s regime in 2011. The Irish Republican Army (IRA) was known to have used Semtex in attacks throughout Northern Ireland and mainland Britain. C-4, another nitroimine-based plastic explosive developed by the U.S. military, is valued for its malleability and potency, although its high cost limits widespread availability.
ANFO explosives—produced by combining ammonium nitrate fertilizer with fuel oil—are especially favored for use in vehicle-borne IEDs. The IRA and the Liberation Tigers of Tamil Eelam (LTTE) deployed ANFO in high-profile bombings in the United Kingdom and Sri Lanka, respectively. One of the most infamous uses of ANFO was by Timothy McVeigh in the 1995 Oklahoma City bombing, where a two-ton ANFO bomb destroyed the Alfred P. Murrah Federal Building. Similarly, plastic explosives were employed in the failed attempt by Richard Reid, the so-called “shoe bomber,” to detonate a device aboard American Airlines Flight 63 by concealing the explosive material in his footwear.
Mines represent another category of explosive devices frequently utilized by terrorist groups, particularly for their effectiveness as concealed, passive weapons. Designed for subterranean deployment, these devices are typically buried and function as booby traps, detonating upon pressure from foot traffic or vehicular movement. Antipersonnel mines are primarily employed to inflict casualties on individuals, while anti-tank mines are designed to disable or destroy vehicles. Various terrorist and insurgent groups across the Middle East, Asia, and Latin America have incorporated mines into their operational tactics.
Homemade explosive devices encompass a range of weapon types, including gasoline bombs, pipe bombs, vehicular bombs, and barometric bombs. Among these, gasoline bombs—commonly referred to as Molotov cocktails—are particularly prevalent due to their simplicity and ease of construction. These incendiary devices are typically assembled by filling a glass bottle with gasoline and inserting a cloth wick, which is ignited immediately prior to being thrown at a target. Terrorist groups have favored gasoline bombs over other forms of improvised explosives for their accessibility and effectiveness in low-resource environments. Pipe bombs, another frequently used homemade device, are constructed by filling a sealed metal pipe with explosive material. These devices are relatively simple to assemble and have been used in a variety of attacks. For instance, pipe bombs have been deployed by single-issue terrorists targeting abortion clinics in the United States. A notable example of their use occurred during the 1996 Summer Olympics in Atlanta, Georgia, when a pipe bomb concealed in a knapsack was detonated by a domestic terrorist, resulting in one fatality and injuring 112 individuals.
Vehicular bombs—improvised explosive devices concealed within cars, trucks, or other vehicles—are frequently employed by terrorist organizations due to their mobility, capacity to carry large quantities of explosives, and difficulty of detection. Their use allows for the targeting of high-value or heavily secured areas with devastating effects. Another specialized form of explosive device, the barometric bomb, is triggered by changes in atmospheric pressure and is particularly suited for targeting aircraft at specific altitudes. The most well-known example is the bombing of Pan Am Flight 103 in December 1988, in which a barometric device detonated mid-flight between London and New York, resulting in the deaths of all 259 passengers and crew.
Regardless of the type or source of the explosive—whether improvised or commercially manufactured—all bombs require a detonation mechanism. Terrorist groups typically employ sophisticated triggering systems to enhance control over the timing, placement, and impact of the explosion. Common types include time-delay switches, mechanical fuses, pressure-activated triggers, electronic detonators, and advanced high-technology ignition systems, each chosen based on the tactical requirements of the operation.
Figure 1 below illustrates the number of attacks involving firearms, explosives, IEDs, and unmanned aerial vehicles (UAVs) from 2020 to 2024. While terrorist groups have consistently relied on firearms as a primary weapon, the use of explosives has shown a marked upward trend in recent years. This growing preference for explosives appears to have influenced a relative decline in the deployment of IEDs. Nevertheless, it is essential to note that groups such as the Islamic State in the Greater Sahara (ISIS-GS) and the al-Qaeda-affiliated Jamaat Nusrat al-Islam wal-Muslimin (JNIM) continue to utilize IEDs extensively in rural areas of Burkina Faso, Mali, and Niger. Additionally, a notable emerging trend is the increased use of UAVs by terrorist organizations, with UAV-related attacks rising sharply from 209 in 2023 to 503 in 2024. While Iran-backed groups such as the Houthis, Islamic Resistance in Iraq, and Hezbollah have employed UAVs—often supplied by the Tehran regime—this tactic has also been adopted by jihadist groups in the Sahel using modified UAVs with explosive payloads, as well as revolutionary movements such as the National Liberation Army (ELN) in Colombia.
Since 2022, GTTAC has documented a significant rise in terrorist attacks involving the use of explosives, as illustrated in Figure 2. In 2018, such incidents accounted for 34% of all recorded terrorist attacks. This proportion declined to 16% in 2019 and remained relatively stable at 17% through 2022. However, a clear upward trend has emerged thereafter, with the share increasing to 24% in 2023 and further to 31% in 2024. Several factors contribute to this resurgence. First, the growing technological sophistication of terrorist organizations has enhanced their capacity to manufacture and deploy explosive devices. Second, the role of state-sponsored terrorism has become increasingly prominent, particularly through the activities of Iran-backed groups. Notably, the surge in attacks by Hezbollah and the Houthis following Hamas’s October 7 terror attacks has played a critical role in driving the recent escalation in explosive-related incidents.
As illustrated in Figure 2 above, although the number of explosive-related terrorist attacks increased, the number of fatalities associated with these incidents declined in 2024. The proportion of deaths resulting from such attacks was at its lowest in 2021, at 8 percent. This figure rose to 11 percent in 2022 and further to 19 percent in 2023, primarily due to the GTTAC recording over 1,300 fatalities in the Hamas-led terror attacks on October 7.
The disaggregation of explosive types in Figure 3 reveals that rockets, mortars, missiles, mines, and grenades have been among the most frequently employed by terrorist organizations. In 2024, the GTTAC documented a notable increase in rocket and missile attacks, primarily driven by intensified operations carried out by Hezbollah and the Houthis in the Middle East. In contrast, the use of mortars and landmines has shown a declining trend. However, grenades have remained a consistently utilized weapon, particularly by terrorist groups operating in Pakistan, India, and countries across the Sahel region.
Finally, GTTAC’s analysis of explosive use by Hamas, Hezbollah, ISIS-Core in Syria, and al-Shabaab between 2018 and 2024 reveals that ISIS-Core was the most active group in deploying grenades and landmines, with 177 grenade attacks resulting in 356 fatalities and 239 mine-related incidents causing 530 deaths. Al-Shabaab followed closely, carrying out 131 grenade attacks that led to 396 fatalities. In terms of mortar use, al-Shabaab was also the predominant actor, conducting 138 attacks that resulted in 438 deaths. Rocket attacks were most frequently attributed to Hezbollah and Hamas: Hezbollah carried out 953 such attacks, resulting in 46 fatalities, while Hamas conducted 499, leading to 20 deaths. Moreover, missile attacks—totaling 315 incidents and resulting in 60 fatalities—were primarily attributed to Hezbollah.
In conclusion, global counterterrorism efforts have yet to yield the anticipated results, as terrorist organizations continue to adapt by adopting new strategies and integrating emerging technologies into their operations. Recent attacks have increasingly involved the use of explosives and unmanned aerial vehicles (UAVs), offering insights into the sources and networks facilitating the procurement of these materials. The operational capabilities of groups such as Hezbollah, the Houthis, and Hamas—particularly their access to advanced explosives and UAVs—point to the involvement of state sponsors, most notably the Tehran regime, in supporting and enabling such activities.