The following is a special installment of “ISIS Redux: The Central Syria Insurgency,” covering the final month of the Syrian regime’s existence and the implication of Assad’s downfall on the future of ISIS. All previous 2024 monthly installments can be found here, as well as a review of developments throughout 2023, 2022, and 2021. A full background on and analysis of ISIS’s resurgence in Syria, including the methodology used to collect this data, can also be explored here, here, and here.

ISIS carried out at least six confirmed attacks in November in the Homs, Hama, and Deir Ez Zor governorates, killing at least eight pro-regime soldiers and two civilians. There were also two high quality* attacks carried out during the month. ISIS attacks in central Syria declined for the third consecutive month, dropping to their lowest point since January 2023. However, attacks did not diminish in other parts of Syria, and the regime’s downfall has given ISIS new avenues to expand while also opening new ways to counter the group. 

ISIS’s nearly ten-month long campaign across central Syria ended this summer and the group has since faced several apparent setbacks. ISIS’s likely exhaustion from such a sustained level of operation was then compounded by the double blow of heavy regime operations in September and early October and three sets of U.S. airstrikes targeting ISIS training camps in the Badia, on September 16, October 12 and October 28, which killed at least 63 militants. 

Facing these challenges, ISIS has shifted its focus in recent months from central Syria to the northeast, expanding its operations against the U.S.-backed Syrian Democratic Forces (SDF). According to one SDF official who spoke to the author, October and November saw a marked increase in ISIS attacks in the northeast, a trend which continued even into the final two weeks of Assad’s rule. Yet the group’s Badia cells also remained attentive, with two ambushes each against security forces in Deir Ez Zor and the north Sukhnah countryside in Homs, leaving at least eight soldiers dead.

Potential for ISIS Growth 

On December 6, the regime’s security forces began to quickly withdraw from Deir Ez Zor as part of the army’s broader collapse. The SDF initially tried to fill this vacuum by advancing across the river, but locals also rose up reclaiming their towns. Many regime-backed National Defense Forces (NDF) fighters simply ‘switched sides,’ claiming their towns were now liberated, and began occupying nearby regime bases. By December 11, the SDF had been pushed out of all of the former regime areas. The downfall of Assad and the return of ex-regime Arab areas to local ownership has triggered some unrest in Raqqa. On December 8 people in western Raqqa and in the Karamah area east of Raqqa rioted against and attacked local SDF forces, triggering a violent response. On December 12 a protest in Raqqa City turned violent when someone shot at an SDF vehicle that tried to break up the crowd. ISIS’s long-time presence across the areas means the organization can easily infiltrate the legitimate peaceful protests to trigger a violent SDF response and further sow chaos and discord in these communities.

The renewed fighting north of Raqqa also provides ISIS with new opportunities. The capture of Manbij by the Turkish-backed Syrian National Army and continued attacks on and around Kobani will have disrupted local security efforts and diverted much of the SDF’s attention and resources from the ISIS fight. This resource strain is compounded by the SDF’s decision to send many units deep into former regime areas in Aleppo, Raqqa, and Deir Ez Zor over the past two weeks in order to try to expand its own territory. Manbij has seen intermittent ISIS attacks over the years and was almost certainly a central smuggling hub for ISIS movement between the SDF and SNA regions. The security and governance upheaval in that city may give ISIS cells the room they need to deepen their roots or expand their presence.

To the west, there are concerning reports that ISIS has expanded in Homs and Hama. As regime lines collapsed in western Syria, security forces in the Badia began to pull back to the major cities. ISIS cells quickly entered al-Kawm, Taybeh, and Humaymah in eastern Homs, though their territorial advance appears to have stopped there. However, infiltrations further west likely continued. In Qaryatayn, the rural city along the Homs-Damascus border, two men have been murdered since the regime’s expulsion. ISIS cells have been trying to re-infiltrate this city for many years, as documented and discussed in this series. On December 9 a White Helmets member was killed in the city and on December 12 the director of the Shaer Gas Field was assassinated. No one has claimed responsibility, but it is possible that ISIS cells carried out these murders.

In Hama, one local told the author that formerly displaced “Bedouins” have been returning to the Salamiyah countryside and looting and robbing the Ismaili and Alawite villages along the desert’s edge. These communities were disarmed as part of their surrender deal with HTS, and HTS does not appear to have established any permanent police force inside Salamiyah yet (overstretched as the group is by establishing police forces on the coast and in major cities). Some of these Bedouin locals once formed the core of local ISIS support in eastern Hama, back when the group’s territory reached the edge of the city. Local and non-local ISIS fighters have conducted multiple massacres in these frontier towns during the course of the war, most recently in May 2017. The removal of both regime and local security forces—and the return of displaced Sunni locals—now opens the possibility of ISIS cells re-establishing themselves close to the Ismaili and Alawite communities for the first time since their territorial expulsion in late 2017. 

New Opportunities to Counter

However, the withdrawal of regime and Russian forces from central Syria has enabled the Coalition to finally strike ISIS camps at will. These areas either remained unknown or inaccessible to pro-regime forces, or regime leaders and Russia were simply uninterested in targeting them. On December 8, U.S. aircraft targeted more than 75 ISIS camps, leaders, and operatives across central Syria, likely dealing a massive blow to the organization. These camps have been the heart of ISIS’s resiliency since 2019 and play an integral role in the organization’s recruitment and training process. Locals reported additional U.S. airstrikes a few days later against ISIS forces who had gathered to attack the key cities of Palmyra and Sukhnah, preventing them from falling to the group. 

The continued U.S. presence in Syria is now even more important, as the freedom of operation provided by the downfall of the regime means that Coalition forces can exploit any attempt by ISIS to gather in large enough numbers for serious attacks. This will likely reduce the group’s activity to a more typical but low-intensity insurgency in western and northeast Syria. Already there have been reports from forces in eastern Homs that many ISIS cells have left the Badia for northeast Syria, fleeing the consistent U.S. airstrikes against their camps and gatherings.

In the chaos of the regime’s withdrawal and downfall, ISIS cells almost certainly infiltrated westward into the Damascus and Homs countrysides. These cells will likely try to build new networks in the cities and conduct intermittent IED or small arms attacks—either against civilians, minorities, or the new government. However, HTS has a wealth of experience fighting ISIS, particularly as a semi-urban insurgency, and will likely be able to dismantle the vast majority of these networks fairly quickly. The downfall of Assad and potential for new political and economic stability will also greatly reduce ISIS’s ability to find allies and recruits among Syrians. Even in eastern Syria, where most recruitment has occurred, the potential for an SDF-HTS negotiated handover of Arab areas will remove many core pressure points that have pushed youth and ex-ISIS members back to the group. 

HTS and the new government’s security forces will also need to quickly move to replace regime security in the Badia. While it may take some time for HTS to set up proper checkpoints and patrols across the Badia, the group will likely do a better job than the regime. As with the urban areas along the Euphrates, securing central Syria relies on effective collaboration with local tribes and communities. Here HTS should excel, building out a local security network supported by more professional HTS units. But the group needs to move quickly to fill in the gap left by regime.

HTS-SDF cooperation (or the folding of the SDF into the new government’s forces) also means there is a strong likelihood there will be a significant reduction in al-Hol’s population next year as western Syrians get released and returned. Despite the security risks, the new government in Damascus may be able to negotiate a deal where-in they take on the role of resettling families from al-Hol in exchange for international financial and technical support in employment and de-radicalization programs for the returnees. Such a process would greatly accelerate the dismantling of al-Hol camp and significantly reduce the threat of a future ISIS resurgence. However, this would certainly be a low-priority initiative for HTS, given the breadth of challenges it currently faces. 

Future Outlook

Insurgent groups always seek to exploit instability and chaos to expand their operations and avoid being uprooted. ISIS will no doubt be able to use these first days and weeks after Assad’s fall to do just that, especially regarding infiltrating major urban areas in western Syria. However, the Coalition airstrikes have prevented any significant gains (such as access to the weapons depots in Palmyra and Sukhnah) while also deeply degrading ISIS infrastructure in central Syria. Most importantly, Assad's departure removes ISIS’s most important tool. The regime’s existence was key to enabling the expansion of ISIS via recruitment and both intentional and corruption-linked materiel support. As the new Damascus government expands its service provision and control over rural Sunni areas, and as sanctions are lifted and the economy improves, ISIS will find ever-shrinking opportunities to recruit the next generation of fighters.  

There may be an initial period of unrest, with one-off ISIS attacks in Damascus, Homs, or rural Salamiyah. However, currently there are more factors against the group than for it. International efforts to help stabilize this new Syria will be crucial for ensuring a swift roll back of any gains the group has made over the past week. Similarly, ending the fighting in northeast Syria, dismantling the SNA, and negotiating a deal that sees Kurdish areas retain full rights and security while Arab areas can choose to be governed by Damascus is critical to reducing the threat of an ISIS expansion in that region. 

*High quality attacks are defined as attacks behind frontlines, attacks that result in seized positions, target regime officers, or involve coordinated attacks on multiple positions, “flying checkpoints” (temporary roadblocks ISIS fighters establish in order to stop and extort or ambush a few cars), ambushes on military convoys, or attacks on checkpoints that kill at least three soldiers or lead to POWs.