How ISIS May Respond to HTS’s Takeover: Rivalries, Strategy, and Future Challenges in Syria
Abstract: This article explores the growing influence of Hay’at Tahrir al-Sham (HTS) in Syria and the potential responses of ISIS, a longstanding rival, to HTS’s expanding control. HTS is seeking legitimacy and has garnered tacit approval from Western governments and regional actors, including the European Union, which is engaged in pragmatic relationships with the group due to the ongoing Syrian refugee crisis. The United States also closely monitors the situation as dynamics shift in the region. According to the Global Terrorism and Trends Analysis Center (GTTAC) database, which recorded nearly 8,000 attacks in Syria by 88 different terrorist groups from January 2018 to October 2024, ISIS remains the most dominant actor in terms of attack frequency, group size, and global reach. Despite some speculation about whether ISIS might withdraw from the region, its increasing operational capabilities and well-established presence suggest it will continue to challenge HTS’s leadership. The historical rivalry between ISIS and HTS raises the likelihood of ongoing conflict. While temporary ceasefires may occur, ISIS is expected to exploit any weaknesses in HTS’s governance, posing a significant challenge to long-term regional stability. Ultimately, ISIS’s resilience and strategic adaptability may undermine HTS’s attempts to consolidate power, further destabilizing Syria’s future trajectory.
Hay’at Tahrir al-Sham’s (HTS) takeover of Syria has raised several key questions regarding its ability to function as a legitimate state. These concerns include whether HTS can form a government, create a constitution that ensures equal rights and representation, and uphold women’s rights, particularly given fears that women may face pressures similar to those under the Taliban. There are also questions about how Islam might be exploited under HTS’s leadership, and how Turkiye, a country that has distanced itself from democratic values, might effectively guide HTS. Additionally, there is the challenge of reshaping the radical ideologies of jihadist groups under HTS’s control and determining how other factions in Syria will respond to HTS’s leadership. According to the Global Terrorism and Trends Analysis Center (GTTAC) Records of Incidents Database (GRID), 88 non-state actors are involved in Syria from January 2018 to October 2024, including Salafi-jihadist terrorist groups, Turkish-backed rebel groups fighting Kurdish forces, Iran-backed groups, Russia-backed groups, pro-Assad forces, and Kurdish groups. Among these, ISIS remains the most established and capable, with a significant presence in size, number of attacks, and extensive global network. This article focuses on Turkiye’s potential role in guiding HTS and examines how ISIS might respond to HTS’s leadership, taking into account the long-standing rivalries and struggles for dominance in conflict zones like Syria.
Despite being confined to a relatively small region, such as Idlib, and relying primarily on conventional terrorist tactics, HTS’s successful consolidation of control in Syria has been both surprising and noteworthy. This shift in power appears to have been tacitly accepted by both Western and regional leaders. For European Union countries, this development may be seen as a preferable outcome, as Syria has become a major source of refugees flowing into Europe. Rather than managing the complex refugee crisis, it may appear more pragmatic to contain the refugee population within Syria’s borders.
Similarly, the United States has not actively opposed HTS’s governance, mainly due to the broader shift in U.S. foreign policy priorities. The Middle East, once a central focus, has become less significant in light of Russia’s expanding territorial ambitions and China’s growing regional and global influence. In response, the U.S. has reoriented its strategic focus toward countering these two powers. This strategic shift was exemplified by the U.S. withdrawal from Afghanistan, which left the Taliban in control of the country. For the U.S., the primary concern remains preventing large-scale terrorist attacks akin to those of September 11, 2001, while safeguarding American interests abroad. Although both Al-Qaeda and ISIS continue to present substantial threats, U.S. security experts assess that their operational capabilities are primarily constrained to specific regions in which they remain active.
Abu Mohammad al-Julani, the leader of HTS, has demonstrated a calculated shift in his leadership approach, frequently engaging with international media to shape his image. He consciously refrains from presenting himself as an immediate threat to the United States, avoiding direct antagonism towards U.S. policies or Israel. Instead, al-Julani has emphasized the need for national unity, articulating plans to establish a constitution that encompasses the interests of all Syrians. This rhetoric contrasts sharply with his earlier tenure in Idlib, where authoritarian practices, including widespread repression and the torture of detainees, characterized HTS’s governance. In a marked departure from the past, al-Julani now seeks to project an image of moderation and clemency. This strategic evolution can be understood as part of al-Julani’s broader effort to secure political legitimacy and establish HTS as a recognized, lawful authority within Syria’s fragmented political landscape.
Despite al-Julani’s rhetoric of peace and inclusivity, it remains uncertain whether he possesses the necessary skills to govern a nation. His background is rooted in military conflict, having played a key role in the early years of Al-Qaeda in Iraq (AQI) and later in the formation of Jabhat al-Nusra, with the support of ISIS leader Abu Bakr al-Baghdadi in Syria. While al-Julani has demonstrated expertise in insurgency and terrorist tactics, his leadership appears ill-suited for the complexities of statecraft. As a result, the United States has designated HTS as a foreign terrorist organization and placed a $10 million bounty on his head.
President Recep Tayyip Erdoğan of Turkiye has emerged as a key actor in the Syrian conflict, notably through his support for various rebel factions seeking to topple the Assad regime. A significant moment in this context occurred when Erdoğan’s Chief of Intelligence visited Damascus and prayed at the Umayyad Mosque on December 12, 2024, a symbolic gesture that harkened back to Erdoğan’s 2012 statement, “We will go to the Umayyad Mosque shortly and pray there.” This remark underscored Turkiye’s assertion of military capability to intervene in Syria and to challenge the Syrian government’s forces. Despite this rhetoric, however, the effort to undermine the Assad regime took over twelve years, involving numerous rebel groups—many of which are documented in global terrorism databases, including the National Liberation Front, Syrian National Army, Syrian Liberation Front, and Jaysh al-Islam—before a tangible shift in power dynamics was achieved.
In addition to supporting opposition groups, Erdoğan has suggested that Turkiye could help Hay’at Tahrir al-Sham (HTS) draft a new Syrian constitution. However, this proposal raises significant concerns about the legitimacy of Turkiye’s involvement, given Erdoğan’s own authoritarian policies. Under his leadership, Turkiye has experienced a decline in democratic values, including the erosion of secularism, the imprisonment of journalists, and the suppression of political dissent. Furthermore, Turkiye’s government has been accused of imprisoning hundreds of thousands of people without sufficient evidence, as reported in the U.S. Department of State’s 2023 Country Reports on Terrorism.
Erdoğan’s government has also been associated with corruption, including the misappropriation of public funds and the consolidation of power by his inner circle. These actions stand in stark contrast to the democratic ideals that would be necessary to guide Syria through a genuine process of political transition. Given Turkiye’s record of undermining democratic norms at home and its increasing authoritarianism, the role of Erdoğan’s government in Syria’s constitutional reform process remains highly problematic. The prospect of a successful, inclusive, and peaceful political resolution under an HTS-led government with Turkish backing seems highly unlikely.
In addition to HTS’s evolving image and Turkiye’s strategic interests in Syria, another critical question is how ISIS will respond to HTS’s consolidation of power. Although ISIS originally emerged as an offshoot of Al-Qaeda, it has since sought to surpass its predecessor in its ambition to establish itself as the preeminent “caliphate” of the Islamic world. This rivalry continues to play out in regions such as the Sahel and Afghanistan, where both groups compete for influence. Given their historical tensions and ideological differences, it remains uncertain how ISIS will interact with HTS in Syria. The potential for conflict between these two groups is high, as their divergent objectives and territorial aspirations may lead to further hostilities in the region.
ISIS is considered one of the deadliest terrorist organizations in modern history. At its peak in 2014 and 2015, the group controlled extensive territories across Iraq and Syria, ruling over six million people. During this period, ISIS also expanded its influence through a network of regional affiliates. These affiliates, located in countries such as Afghanistan, Nigeria, Somalia, Libya, the Sahel region, Mozambique, and the Democratic Republic of Congo, significantly broadened ISIS’s reach and impact. Despite its territorial losses in Syria, ISIS continues to pose a substantial threat, largely due to the ongoing activities of its global franchises, which maintain the group’s presence and operational capacity worldwide.
The global coalition against ISIS has made significant strides worldwide, with U.S. forces, in collaboration with Kurdish groups, successfully driving ISIS militants to the outskirts of Syrian territory. In response to these intensified operations, a notable portion of ISIS fighters relocated, with some joining ISIS’s affiliate in the Sahel (ISIS-Greater Sahara) and others moving to the group’s branch in Afghanistan (ISIS-Khorasan). U.S. military actions further disrupted ISIS’s organizational structure, leading to the elimination of several senior leaders in 2020 and 2021.
Recent international reports suggest that ISIS’s leadership has primarily re-established itself in Somalia. Despite this geographical shift, the group continues to pose a significant threat in Syria. From January 2018 to October 2024, ISIS conducted 2,036 attacks, accounting for approximately 25% of all incidents in Syria during this period. Notably, the frequency of ISIS attacks has steadily increased, rising from 187 in 2018 to 416 in the first ten months of 2024, reflecting both the group’s persistence and its adaptive strategies in response to external pressures.
Figure 1: The Number of ISIS Incidents in Syria, January 2018 to October 2024
ISIS remained the deadliest terrorist organization in Syria. While the group’s lethal impact decreased from its peak years in 2014 and 2015, it was still responsible for 2,312 fatalities in 2018 alone. Over the following years, the number of deaths fluctuated, but ISIS consistently caused at least 800 fatalities annually. Crucially, the number of deaths consistently exceeded the number of injuries from January 2018 to October 2024, underscoring ISIS’s focus on inflicting maximum harm through high-caliber weapons and coordinated attacks.
Figure 2: Number of People Killed and Wounded in ISIS Attacks, January 2018 to October 2024
An important indicator of ISIS’s operational activity is the geographic distribution of its attacks across Syria. In 2018, the group launched attacks in all 12 Syrian provinces, a pattern that persisted in subsequent years. As illustrated in Figure 3, Dayr ar Zawr emerged as the most active province, with ISIS conducting a total of 1,019 attacks from 2018 to October 2024. This province has thus served as the group’s primary base of operations. Other provinces with notable levels of activity include Homs (308 attacks), Ar Raqqah (195 attacks), and Al-Hasakah (192 attacks). As of October 2024, ISIS conducted 237 attacks in Dayr ar Zawr, 83 in Homs, and 51 in Ar Raqqah. Remarkably, ISIS was active in seven of Syria’s 12 provinces in 2024, further reinforcing the group’s sustained presence and operational capacity across the region.
Figure 3: Locations of ISIS Attacks, January 2018 to October 2024
In addition to its geographic spread, ISIS’s tactics also provide insights into its operational capacity. The group targeted military forces in 25% of its attacks and employed improvised explosive devices (IEDs) in 21% of its incidents in the same period. These figures highlight ISIS’s reliance on asymmetric warfare methods, enabling the group to continue its operations against both military and civilian targets effectively.
The GTTAC data underscores the increasing capabilities of ISIS, while HTS’s stance toward Kurdish groups remains uncertain. The survival of Kurdish factions under HTS control largely hinges on U.S. support, especially in opposition to groups that Turkiye classifies as PKK-linked. If U.S. support diminishes, these Kurdish groups could face considerable difficulties under HTS leadership, potentially creating risks for HTS as well.
Turkiye’s alleged relationship with ISIS has raised significant concerns, particularly regarding its potential role as an intermediary between HTS and ISIS. Between 2014 and 2018, Turkiye is reported to have facilitated the movement of over 30,000 ISIS militants across its borders, while allegedly turning a blind eye to the group’s procurement of weapons and logistical support. Notably, in 2014, Turkish authorities intercepted a truck carrying explosives en route to Syria, reportedly intended for jihadist groups. However, the officers involved in this interception were subjected to severe judicial proceedings and remain in solitary confinement to this day. Since that incident, there have been no reports of similar investigations into weapons shipments. A particularly concerning development is the recent release of ISIS militants involved in the 2016 Istanbul airport bombing, which resulted in the deaths of 45 people. Despite being sentenced to multiple life terms, these individuals were unexpectedly freed, fueling further speculation about Turkey’s strategic relationship with ISIS and the possibility of a deal in its intermediary role.
The United States is closely monitoring the ongoing conflict in Syria and, while initially reluctant, may eventually tacitly support an HTS-led government, contingent upon HTS’s severance of ties with Al Qaeda. However, the reliability of HTS’s commitment to this condition remains uncertain. Given the precedent established by the Taliban’s provision of sanctuary to Al Qaeda in Afghanistan, there are concerns that HTS may similarly offer refuge to Al Qaeda in Syria. Despite shifts in HTS’s public rhetoric, the group’s ideological alignment with Al Qaeda persists, posing significant challenges to the full severance of their relationship.
In conclusion, the consolidation of power by HTS in Syria raises several significant questions about the country’s future trajectory. Foremost among these are whether Turkiye can successfully manage Syria’s transition towards peace, facilitate the return of millions of Syrian refugees, and ensure long-term stability. Another key concern is how ISIS will respond to HTS’s leadership, given the historical rivalry between the two groups and ISIS’s established presence in the region. As the most capable and operationally effective terrorist group in Syria, ISIS continues to pose a significant challenge for HTS. This is evident in ISIS’s sustained military activity, which includes a high frequency of attacks across multiple Syrian provinces, the strategic deployment of explosives and improvised explosive devices (IEDs), and its ability to employ complex and diversified terror tactics. While ongoing negotiations between HTS and ISIS could lead to a temporary détente, ISIS is likely to remain resilient and opportunistic. The group may seek to exploit any potential weaknesses or failures within HTS’s governance, thereby enabling it to regain influence and destabilize the region further. Consequently, despite any short-term agreements, ISIS is expected to remain a formidable force, capitalizing on the vulnerabilities inherent in the HTS-led governance model.
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