The Islamic State (ISIS) in Syria
Introduction
In the six weeks between the December 8, 2024, overthrow of former Syrian President Assad and the inauguration of President Trump, the United States (US) quietly widened the territorial scope of its counter-terrorism footprint in Syria more than three-fold, an unprecedented expansion not seen even at the height of the U.S. anti-ISIS campaign from 2014-2017.
The purpose of this growth has been to fill the void left by outgoing Russian troops. Prior to Assad’s ouster, Russian forces were responsible for anti-ISIS operations in the regime-controlled area south of the Euphrates River, per a de-confliction agreement reached between Washington and Moscow in 2015.
Starting in 2024, ISIS activity in Syria increased significantly, with the group’s attacks tripling compared to 2023. This growth pushed the US to breach the deconfliction agreement for the first time in September–October 2024, launching airstrikes targeting ISIS cells south of the Euphrates River that killed more than 100 of the group’s fighters and leaders.
The US Presence in Syria
Since the overthrow of Assad, the United States is now the sole foreign power in Syria both capable and willing to confront ISIS. As a result, the US military has launched an unprecedented number of airstrikes in Syria’s Central Desert, a sparsely populated 80,000 kilometer2 expanse home to a series of rugged, impenetrable mountains which has served as ISIS’ primary base of operations since 2019.
American aircraft have since been seen conducting aerial patrols in areas as far off as Suwayda, Syria’s southernmost province. In the Syrian capital of Damascus, U.S. intelligence was critical in foiling a failed ISIS suicide attack on the Sayyida Zaynab shrine—one of the holiest sites in Shi’a Islam—on January 11 2025.
ISIS’ Syria Strategy
Rather than the group’s ability to carry out attacks in Syria itself, the United States should be far more concerned with ISIS’ efforts to exploit the normalization of Salafi-Jihadism under the country’s new regime, which the group could use as cover to spread its ideology, strengthen its recruitment and revenue streams, and collect resources that can be redeployed abroad.
Since 2019, ISIS attacks in Syria have concentrated in key parts of the Central Desert home to large oil, gas, and phosphate reserves, and other revenue generating infrastructure, whose operations the group seeks to tax and extort in order to self-finance and survive as an organization. Now, ISIS will likely exploit Syria’s takeover by Hayat Tahrir al-Sham (HTS)—the Salafi-Jihadist group which exerts de-facto control over the country’s interim government—as cover to better integrate into local society and insert its operatives deeper into commercial and black-market sectors of the economy.
HTS will undoubtedly seek to prevent this, having launched its own series of crackdowns against ISIS and al-Qa’ida since 2018, often with assistance from the US. It must be noted that since 2019, the US has launched more than two dozen operations in HTS and other rebel held areas that killed more than 100 ISIS and al-Qa’ida operatives. Among those killed were two ISIS caliphs and dozens of the group’s first and second tier leaders, including those planning terror attacks abroad.
These high-profile killings, however, point to an uncomfortable truth. Prior to Assad’s overthrow, HTS and other rebel held areas were home to a far higher concentration of top-level ISIS and al-Qa’ida leaders than any other part of the country. This was largely due to the Sunni Islamist and Salafist nature of Syria’s rebel movement, whose modes of dress, outward appearance, religious rituals and ideology more closely resemble those of ISIS than they do fighters from the former Assad regime, or the Kurdish dominated Syrian Democratic Forces (SDF).
ISIS and Syria’s rebel movements have also historically recruited from within the same or similar networks in Syria’s Sunni communities, creating significant overlaps and even kinship ties between both sides’ membership.
Perhaps as a result, prior to Assad’s overthrow HTS and other rebel held areas consistently saw the lowest number of ISIS attacks compared to other parts of the country. This was likely deliberate on the part of ISIS, and a component of a broader strategy by the group’s leadership to better embed themselves amongst rebel groups and avoid scrutiny in order to oversee and plan worldwide operations.
Going forward, ISIS’ efforts to integrate will be made easier by the fact that HTS has alliances with nearly a dozen other Salafi-Jihadist groups operating in Syria, which include thousands of Uighur, Uzbek, Tajik, Circassian, Afghan, Chechen, Albanian, and Arab foreign fighters, some of whom are under US sanction.
Many of these groups, in particular, Ansar al-Tawhid and the Turkestan Islamic Party (TIP), have absorbed many former ISIS and al-Qa’ida militants that defected from both groups following periods of crackdown by HTS. On December 30, 2024, HTS shocked many Syrians by appointing 6 Uighur, Jordanian, Turkish, Tajik, and Albanian fighters to the ranks of colonel and brigadier general within the country’s new army. This move serves as an indication of the influence foreign jihadists will wield in the new Syria.
Recommendations
Moving forward, the United States should focus its operations on the parts of Syria which are home to the country’s most valuable revenue generating infrastructure. Furthermore, the US should use the prospect of sanctions relief to incentivize Syrian leaders to grant US intelligence assets full access to these sites. Currently, the US-backed SDF, in northeast Syria, still controls dozens of prisons. These facilities house more than 9,000 ISIS fighters and 40,000 of their family members, an “army in detention” according to US officials. In January 2022, ISIS cells launched a 10-day assault on one such prison, enabling several hundred of its members to escape including several dozen high ranking leaders.
Should ISIS be allowed to regroup, these prisons will likely be their first target, followed by others abroad. To prevent this, the United States should focus first on combatting ISIS’ ability to self-finance. Doing so will require expanded operations in several key regions.
Phosphate Mines
On December 5, 2024, as Assad’s forces were collapsing around the city of Homs, ISIS announced that it had taken over territory near Khneifis, Syria’s second largest phosphate mine in the heart of the Central Desert. The next day, the US-backed Syrian Free Army—stationed at the US base in Tanf, along the Syrian-Jordanian-Iraqi border—marched north and recaptured the area, along with the larger al-Sawana phosphate mines and several nearby towns. However, ISIS’ initial expansion near Khneifis is a dangerous indication of its capabilities and future intentions.
Syria’s phosphate reserves total 1.8 billion tons, the third largest in the world after Morocco and China. Though largely inactive throughout the course of the civil war, Syrian phosphate constitutes a potentially lucrative source of revenue. Starting in 2018, the Assad regime managed to partially revive production at the mines and export between 400,000–650,000 tons of phosphate to European countries per year. Under Assad, extraction and export of phosphate was divided almost entirely between Russia and Iran. This changed in November 2022, when Saudi investors established the Seven Wells for Phosphate Investment LLC in an attempt to increase the kingdom’s investment in the sector. In each instance, the Assad regime gained access to a much-needed source of foreign currency as the country suffered under sanctions.
Syrian phosphate is particularly valuable as it contains relatively low levels of cadmium, a carcinogen whose permitted levels in fertilizer are highly regulated in the European Union. In addition, Syrian phosphate contains 300 grams per cubic ton of depleted uranium. This rate is higher than the 200 grams per cubic ton world average. As a result, Syrian phosphate is extremely useful in the production of sarin, soman, and tabun, which are key elements in the production of chemical weapons.
In the weeks since Assad’s overthrow, local forces operating under the umbrella of the Tribal Council of Palmyra have repelled ISIS attacks on several arms warehouses and other facilities around Palmyra, the largest city in the Central Desert just north of Khneifis. Later, HTS units led by commander Burhan al-Jarallah aka Abu Duma began carrying out sweeps of the al-Amour mountain range north of the city, where ISIS cells are known to congregate.
The future in the area is uncertain. Assad’s removal from power and the withdrawal of Russian and Iranian troops from the Syria mean that foreign investors will likely have new opportunities to expand their footprint in Syria’s phosphate sector. Should activity at Syria’s phosphate mines begin to return to full-production, ISIS cells will likely increase their attacks in the area in the hopes of extorting money from local producers.
Gas
Syria’s Tuwaynan and al-Sha’ir gas fields in the westernmost stretches of Syria’s Central Desert will be among the most important sites for the United States to monitor. In the latter years of Syria’s civil war, both sites combined produced an estimated 6 million cubic meters per day (CMD) of natural gas.
ISIS initially seized Tuwaynan in January 2014, maintaining control of the field until Assad’s forces recaptured the Central Desert in early-2017. During this period, ISIS reached an agreement with HESCO, a Syrian government contractor, and StroyTransgaz, a Russian company, to keep the field operating. According to the deal, ISIS agreed to a 60-40 profit sharing split with HESCO-StroyTransgaz, and allowed Russian engineers to work at the site during the day and return home at night. ISIS attempted to establish a similar arrangement at al-Sha’ir, a much larger gas field with 100 billion CMD in reserves, however failed to permanently keep control of the facility.
Between July 16 2014 and 27 April 2017, both ISIS and the Assad regime each captured and then lost control of the al-Sha’ir field four times. After the loss of its Caliphate in July 2019, ISIS resumed attacks in the area around both Tuwaynan and al-Sha’ir, which quickly became one of the most active theaters for the group in all of Syria.
Three times, between June and December 2020, ISIS cells took over key villages in the east Hama countryside near Tuwaynan. Eventually, ISIS’ position become so strong that Assad’s regime required Russian airpower to dislodge them. In one instance, regime troops were forced to call in a former Minister of Defense, who happened to hail from the area, to lead troops into battle and rally local tribes.
Since then, ISIS has made terrorizing the local population a key feature of its attempts to gain influence in the area. In doing so, they have twice carried out mass kidnappings of tribesmen, and regularly stolen thousands of sheep from herders and merchants. From February to April 2023, ISIS carried out three massacres of dozens of local Bani Khalid and Hadid tribesmen. This move further solidified a blood feud that pushed large numbers of locals from both factions into join pro-Assad militias.
With Assad gone, Bani Khalid and Hadid tribesmen will judge HTS and the United States by the extent to which both actors assist in the feud against ISIS. In an ideal scenario, tribesmen would like to work with both HTS and the US. ISIS’ recent activity around Palmyra—located southeast of the al-Sha’ir field— has likely already begun to worry local tribes, who will be eager to seek support from outside parties.
Oil
Lastly, one of the most crucial regions for ISIS is Syria’s easternmost province of Deir Ezzor. This area is home to the majority of the country’s oil reserves, most of which are located north of the Euphrates River and are controlled by the US-backed SDF since late 2017. Prior to Syria’s civil war, peak production in Deir Ezzor exceeded 200,000 barrels per day (bpd). Recent data estimates say that the number of bpd had dropped to, or below 50,000 bpd.
During the height of its territorial control, ISIS named Deir Ezzor “Wilayat Kheir”, or “the Province of Abundance”. This title was due to the significant wealth the group extracted from the region. Since losing control of the area, the group has carried out a systematic campaign of attacks against local oil merchants on both sides of the Euphrates, demanding they pay ISIS a tax on their production.
Even before the overthrow of Assad, ISIS attacks on oil facilities and merchants, along with robberies and the seizures of tankers, expanded significantly throughout 2024. Furthermore, ISIS regularly issued public and direct threats to specific individuals who resisted its expansion into the sector. In May 2024, for example, ISIS cells hung fliers at mosques across Deir Ezzor warning locals against cooperating with SDF officials Shuheil Muhammad Ramadan and Hamza al-Sayyid.
More than in any other part of Syria, the United States must strengthen its force posture in Deir Ezzor. The increased presence will prevent ISIS from extorting and extracting more revenue from the area. Deir Ezzor’s location on the Syria-Iraq border also makes it a key hub for smuggling and movement by ISIS cells between both countries. A larger presence will be better postured to interdict ISIS smuggling operations between the two country’s porous borders.
Conclusion
HTS is eager to work with the United States to combat both ISIS and al-Qa’ida, in the hopes that doing so will encourage Western nations to lift sanctions. However, HTS must balance these goals with a competing set of commitments to its radical base, which will actively oppose conditions set by Western nations for sanctions relief. These include commitments to democracy, political pluralism, and human rights, along with efforts more to purge radicalism from Syrian institutions.
In Afghanistan, the Taliban has elected to appease its base rather than cave to Western demands. As a result, the country has remained under strict sanctions. However, this strategy may have succeeded in reducing the appeal of the country’s ISIS branch, known as ISIS-K, which controls very little territory in Afghanistan and as a result has resorted to carrying out most of its operations abroad.
Should HTS go the opposite route or at least work harder to thread the needle between both sets of commitments, extremist Syrian and foreign factions in the country may grow disgruntled and radicalize further. This will likely create a wedge that groups such as ISIS and al-Qa’ida may later be able to exploit. The proliferation of radical Salafi-Jihadist groups across Syria may have already provided cover for ISIS operatives to surreptitiously preach radical versions of Islam in parts of the country where such ideas could previously have never been broached to begin with.
Going forward, the United States must anticipate within which sectors and parts of the country ISIS may seek to expand and pre-emptively work to gain oversight over and access to these areas. Failing to do could risk a broader catastrophe that empowers thousands of ISIS and other radical fighters to expand their influence across the country.
