Sleeper Cells: How Likely Is ISIS To Regroup in New Syria?

Since the fall of Bashar al-Assad’s regime, Syria’s new leadership has placed a strong emphasis on ensuring internal stability, chiefly by confronting the lingering threat posed by ISIS sleeper cells still operating in the shadows across the country.

The new Syrian authorities have made notable strides in counterterrorism efforts, drawing on intelligence support from the United States, Turkiye, and several European nations. 

The aim: to prevent any resurgence of the group or its reconstitution on Syrian soil.

Operational Cells

There have been emerging signs—albeit limited for now—of ISIS cells attempting to reassert themselves as a military force within certain Syrian cities.

On May 17, 2025, Syria’s Ministry of Interior reported a successful operation targeting a “hideout belonging to an ISIS-affiliated terrorist cell” in the city of Aleppo, comprising seven members.

The joint security operation, carried out by the General Security Directorate and the national intelligence service, resulted in the neutralization of three militants and the arrest of the remaining four.

In a statement issued via its Telegram channel, the Ministry of Interior declared that the Syrian state remains “determined to crush criminal cells with an iron fist,” adding, “We will not hesitate to safeguard the country’s security and stability, and to confront anyone who dares to undermine it.”

On May 26, 2025, the ministry also announced the execution of a “high-level” security operation near Damascus, which led to the arrest of members of ISIS-affiliated cells. 

According to officials, the group had been plotting to “undermine security and stability.”

In a statement at the time, Brigadier General Hossam Maamoun al-Tahan, head of internal security in the Rif Dimashq governorate, said that several members of ISIS-affiliated terrorist cells had been apprehended while operating across parts of Western Ghouta.

Al-Tahan noted that the cell was found in possession of “a cache of light, medium, and heavy weapons,” as well as “suicide vests they had planned to use in attempts to destabilize security and sow chaos in the area.”

Shortly thereafter, on May 30, 2025, ISIS claimed responsibility for its first attack on Syria’s new government forces since the ousting of al-Assad regime on December 8, 2024.

According to Search for International Terrorist Entities (SITE), a monitoring group that tracks jihadist activity, the group detonated an improvised explosive device targeting a vehicle belonging to the new government forces in the southern province of Sweida. 

The blast killed one person and injured three members of the 70th Division of the newly restructured army. 

The group claimed the bomb had been planted earlier by what it referred to as “the soldiers of the caliphate.”

In a clear sign of ongoing intelligence monitoring of ISIS movements in Syria, U.S. Central Command (CENTCOM) announced the assassination of senior IS figure Rahim Boev in an airstrike on Syria’s Idlib countryside on June 10, 2025.

CENTCOM stated that it had killed an ISIS leader, Rahim Boev, during an aerial operation in northwest Syria.

“This airstrike is part of CENTCOM’s ongoing commitment, alongside regional partners, to disrupt and degrade efforts by terrorists to plan, organize, and conduct attacks against U.S. forces and our allies,” CENTCOM said.

According to CENTCOM, the ISIS leader was involved in planning external operations threatening U.S. citizens.

Poor Choices

The prospect of ISIS exploiting the fall of al-Assad regime to reestablish itself in Syria remains a very real concern.

According to more than 20 sources—including security and political officials from Syria, Iraq, the United States, and Europe, as well as regional diplomats—this is precisely what the group is aiming to achieve, Reuters reported on June 12, 2025.

The sources indicated that IS has begun reactivating its fighters in both Syria and Iraq, identifying potential targets, distributing weapons, and stepping up recruitment and propaganda efforts.

With ISIS remaining a persistent source of threat to Syria’s new government, questions have emerged over the group’s capacity to expand, possibly through tactical shifts aimed at reasserting its presence.

For now, IS’s footprint appears limited to a number of sleeper cells, primarily based in the Syrian desert stretching toward Iraq, where the group has maintained a presence since March 2019. 

However, indicators suggest the threat remains active enough not to be dismissed.

Notably, in the wake of al-Assad’s ouster, the new Syrian administration prioritized the restructuring of the country’s intelligence apparatus, appointing Anas Khattab as head of the General Intelligence Directorate on December 26, 2024.

Hussein al-Salama assumed leadership of the General Intelligence Directorate in early May 2025, following Anas Khattab’s appointment as Minister of Interior.

The agency’s first major security test after the fall of al-Assad regime came on January 11, 2025, when it successfully foiled an attempted bombing by a four-member cell targeting the Sayyida Zaynab shrine, south of Damascus.

At the time, Syria’s newly restructured intelligence service announced it had apprehended the suspects—whom it identified as members of ISIS—and seized a cache of weapons, ammunition, Lebanese documents, and foreign currency in their possession.

Notably, just days after thwarting the attack, U.S. officials revealed to The Washington Post that America had begun sharing classified intelligence with Syria’s new administration concerning the threat posed by ISIS.

The newspaper reported on January 25, 2025, that the U.S. intelligence played a crucial role in preventing the bombing attempt at the Sayyida Zaynab shrine.

Countries invested in Syria’s stability and with shared interests are reportedly encouraging coordinated efforts to combat ISIS and prevent its resurgence.

In a tangible step towards regional cooperation, sources within Turkiye’s Ministry of Defence told the state-run Anadolu Agency on May 29, 2025, that a joint operations centre had been established by five countries to combat ISIS in Syria.

The centre was agreed upon during a meeting held in Jordan on March 9, 2025, attended by the foreign ministers of Turkiye, Iraq, Syria, Lebanon, and the host country.

According to the sources, Damascus has since invited the coordination unit—comprising Turkiye, Syria, and Jordan—to begin its operations in the Syrian capital.

Within this context, Syrian military and strategic expert Fayez al-Asmar dismisses the likelihood that ISIS will be able to regain territorial control over Syrian or even Iraqi geography in the medium to long term.

Speaking to Al-Estiklal, al-Asmar suggested that IS is more likely to resort to hit-and-run attacks, raids, and ambushes carried out by individuals or small clustered groups within Syria.

He also predicted the group would increasingly employ car bombs and improvised explosive devices in an effort to destabilize security and sow chaos across Syria, particularly following the group’s denunciation of Syrian President Ahmed al-Sharaa as an apostate who has “shed his cloak and shaved his beard.”

Al-Asmar downplayed ISIS’s capacity to significantly or effectively recruit local elements within the ranks of Syria’s new army.

“The Syrian state views with heightened sensitivity and scrutiny the entry of foreign nationals affiliated with ISIS into the country,” al-Asmar said, especially amid the growing rapprochement between Turkey, the United States, Europe, and the Syrian president, Ahmed al-Sharaa.

This is also set against the backdrop of enhanced intelligence cooperation aimed at preventing the resurgence of ISIS activities and safeguarding stability, as well as ensuring Syria does not become a fertile ground for planning threats, even against Western nations.

Seeking Support

Tom Barrett, Washington’s ambassador to Ankara and the U.S. president’s special envoy to Syria, hinted that Ahmed al-Sharaa’s efforts to form an inclusive government and court the West could make him a target for extremist groups.

Speaking to the American news site The Monitor on June 11, 2025, “We need to coordinate a protection system around [Sharaa],” Barrett said. 

He also highlighted concerns that foreign fighters who supported al-Sharaa during the revolution—and who are now being integrated into the Syrian army—are at risk of being radicalized once again by groups such as ISIS.

Ahmed al-Sharaa, the transitional Syrian president formerly known as Abu Mohammad al-Julani during his leadership of Hay’at Tahrir al-Sham, led the coalition of opposition factions to topple Assad.

Shortly after assuming power, al-Sharaa announced the dissolution of all armed groups—including Hay’at Tahrir al-Sham, which he had once commanded. 

The group, originally an offshoot of al-Qaeda, severed ties with the network in 2016.

In the years preceding al-Assad’s fall, Hay’at Tahrir al-Sham had established itself as a dominant force in northwest Syria, clashing with ISIS, dismantling its cells, and hunting down its members.

These clashes have deepened the animosity between ISIS and Ahmed al-Sharaa. 

In January 2025, IS released a video threatening to fight the new Syrian administration should it implement United Nations charters and laws.

The group described the factions involved in the Operation Deterrence of Aggression that toppled al-Assad as pawns in the hands of Turkiye and other countries.

In another video published on Telegram, IS declared that “those who call for a civil state in Syria are collaborators and agents of the Jews and Crusaders, and a new tyrant,” in its own words.

ISIS questioned why overthrow al-Assad regime if the revolution is to result in a constitutional government.

The group attacked the Syrian uprising, branding it “jahiliyyah” — a term referring to a state of ignorance — for seeking to establish the concept of a civil state. 

It described the revolution as a liberation from a repressive regime monopolizing power, only to replace it with another democratic system that shares authority.

In this context, Wael Alwan, a researcher at the Jusoor Centre for Studies, told Al-Estiklal that “ISIS will exploit the growing extremist dissatisfaction that is being fuelled by ongoing mobilization and recruitment efforts in Syria.”

ISIS’s strength does not stem solely from its organisational structure but also from the presence of numerous extremists and hardliners who take a hostile stance towards the new government led by al-Sharaa.

Alwan added, “Given the current landscape, ISIS is unlikely to regroup its ranks in Syria without external support, which may come from Iraq.”

The Syrian desert connects with the Iraqi desert, two regions believed to harbour sleeper cells of ISIS.

Alwan warned of concerns that, amid escalating tensions between Israel and Iran, the latter might activate Iraqi cells to funnel logistical and financial support aimed at expanding chaos in Syria and effectively rebuilding ISIS, potentially paving the way for a renewed Iranian influence in the region.

With the fall of Bashar al-Assad, Iran’s foothold in Syria—established since 2011 through billions of dollars spent and tens of thousands of foreign Shia fighters brought in to help the regime withstand the uprising—came to an end.

The collapse of al-Assad’s regime marked a significant and humiliating setback for Tehran, so much so that it was described by prominent Islamic Revolutionary Guard Corps commander Behrouz Esbati as a “crushing defeat for Iran.”