AMMAN: Islamic State sleeper cells are assassinating local officials and laying roadside bombs across eastern Syria, where the militant group is exploiting a fragile security situation despite losing its final territorial foothold in Syria earlier this week.

The Islamic State (IS) attacks have reportedly claimed the lives of dozens of commanders and fighters from the US-backed Syrian Democratic Forces (SDF) in Raqqa, Deir e-Zor and Hasakah provinces since last month, when SDF forces began closing in on the final stronghold of IS fighters in Baghouz.

Although a ground campaign spearheaded by the SDF finally wrested control of the riverside encampment in Deir e-Zor province from IS earlier this week, shootings, bombings and suicide attacks—most either claimed by or attributed to IS—have struck local authorities and US-backed Kurdish forces in other areas of eastern Syria.

Suspected IS sleeper cells have repeatedly attacked Hasakah province, where the SDF is well-entrenched and headquartered, although many of these IS operations have struck remote targets in Syria’s eastern desert rather than urban areas.

Meanwhile, in Deir e-Zor and Raqqa provinces, the current focal point of clandestine IS activity, a half dozen local officials, journalists and civilians describe near-daily attacks and widespread fears of escalating violence in former IS-held territory. Their testimonies, combined with reports by local activists and pro-opposition media outlets active in the region, point to a marked increase in bombings and assassinations in recent weeks.

“With IS’ recent battlefield collapse, it’s started resorting to suicide attacks at every chance it sees,” Kanaan Barakat, interior minister of the Kurdish-led Self-Administration that governs most of northeastern and eastern Syria, told Syria Direct.

“And with the SDF’s victory announcement over IS, [the group] will continue striking civilian and military targets,” he added. “They’ve begun using new types of operations: sleeper cells and individual attacks.”

In one of the most recent reported attacks targeting SDF-linked officials and fighters, IS militants opened fire on a checkpoint west of Manbij city in northeastern Aleppo province on March 26, killing seven SDF fighters. Unofficial IS social media channels later claimed responsibility for the attack.

On March 25, an IED explosion in northern Hasakah’s Ras al-Ain killed two fighters from the Kurdish People’s Protection Units (YPG), a Kurdish fighting force that comprises the bulk of the SDF.

And two days before Monday’s explosion, on March 23, an IS cell in northern Hasakah province detonated another roadside bomb, killing a YPG commander and two of the group’s fighters, pro-opposition news outlets reported.

On the same day, other attacks—later claimed by IS through the group’s unofficial social media channels—struck SDF checkpoints and other targets in roughly a half dozen villages and towns across Deir e-Zor province.

While the SDF’s official website and social media channels release statistics for battlefield deaths against IS and Turkish-backed forces in northwestern Syria’s Kurdish-majority Afrin region, there are no statistics for recent insurgent attacks in the east of the country.

Without adequate Internet or statistics released by local authorities in these areas, Syria Direct was unable to independently verify each reported attack.

Several SDF sources were unavailable for comment before publication.

A mounting insurgency?

Analysts and local officials have long warned of a coming insurgency in former IS territory, even after the group’s battlefield defeat. Now, without any territory firmly under its control, IS appears to have launched a burgeoning campaign of hit-and-run attacks.

While the hardline group maintains a scattered presence in the region since losing its last territorial foothold, increased IS activity over the past month signals that the hardline group’s forces remain active in areas formerly under its control.

The transition in tactics is not sudden. The group’s self-proclaimed “caliphate” once controlled a massive swathe of territory across Iraq and Syria, with 10 million civilians living under its control.

After five years of simultaneous ground offensives by the US-backed SDF on one side and the Syrian army on the other, IS’ territory shrank to a small stretch of desert along the Euphrates River in southern Deir e-Zor province late last year.

Surrounded, by February the hardline group’s so-called “caliphate” was limited to a small riverside encampment near the town of Baghouz.

International journalists perched just outside of the camp recorded images and video of a surreal landscape: thousands of fighters, their families and captives living in squalor—the militants flanked on all sides.

Artillery bombardment and airstrikes pounded the camp for weeks as thousands of IS fighters and civilians surrendered themselves to the SDF.

Others holed up along the river’s banks for the final stand-off.

Photos of that final battle’s aftermath, shared by activists on social media, showed a grim scene: burned-out vehicles and the charred bodies of men, women and children littered the hellish camp landscape.

The SDF livestreamed a press conference from Deir e-Zor province on March 24 to announce “victory” over IS. Mustafa Bali, an SDF spokesperson, wrote on Twitter that IS’ “so-called caliphate” had finally been “eliminated.”

Even so, SDF leadership have made it clear that the victory was only partial.

Mazlum Kobane, the SDF’s commander-in-chief, wrote in an op-ed published earlier this week that, although IS’ territorial caliphate has come to an end, “major challenges [lie] ahead” for the region.

Kobane’s report warned of “sleeper cells planted by the terrorist organization,” and the rise of an insurgency “employing tactics of individual terrorist acts such as bombings and assassinations.”

The situation could worsen further after a partial withdrawal of US forces announced by US President Donald Trump earlier this year, that would see the number of American servicemen in Syria drop to only several hundred, Kobani warned.

“The vacuum of power...will undoubtedly be exploited.”

‘Sophisticated efforts’

As the SDF gradually captured territory from IS in Syria’s eastern desert over the past several years, thousands of hardline militants began preparing for an insurgent campaign in eastern Syria long before losing Baghouz, said Institute for the Study of War (ISW) researcher Brandon Wallace.

“The US-backed campaign to defeat the IS pocket along the Euphrates River Valley did destroy IS’ territorial control, but it displaced IS fighters in the process,” Wallace told Syria Direct.

These displaced fighters reinforced sleeper cells in the region, which “started preparations for an insurgency long before the SDF completed ground operations,” he said.

“These cells operate with coordination. The IS insurgent attacks in eastern Syria are well designed.”

Last month, IS militants attempted to assassinate Deir e-Zor Military Council commander Abu Khawla along the Hasakah-Deir e-Zor highway. A day earlier, on February 14, a separate assassination attempt targeted SDF and Deir e-Zor Military Council spokesperson Leilawa al-Abdullah on the same stretch of road.

“These attacks failed, but demonstrate that IS is sophisticated enough to identify and target the officials critical to stabilization efforts,” said Wallace.

Meanwhile, the SDF must also contend with a complex patchwork of local communities: some actively supportive of IS, others suspicious of what they regard as a Kurdish-led force occupying traditionally Arab areas of eastern Syria.

Although the SDF is largely responsible for driving out IS from much of eastern Deir e-Zor and Raqqa provinces, local residents and officials say that certain villages and towns remain hostile to the SDF. Some even remain sympathetic to IS.

Eastern Syria is an ethnically rich region, with Arabs, Kurds, Syriacs and others populating Raqqa, Hasakah and Deir e-Zor provinces. Eight years of war have in many cases inflamed tensions between the groups—something that IS seeks to exploit.

“Once the SDF campaign cleared an Arab area, it left in place a Syrian-Kurdish system of stablization and governance,” Wallace told Syria Direct. “Syria now has several areas with sympathetic populations to IS governed by a structure that is not the product of the local population.”

‘Diverse targets’

The divide between the SDF and local populations allows IS to operate with impunity in many areas technically under SDF control, according to the mayor of one Deir e-Zor town.

“It’s become clear that these IS sleeper cells are activating themselves, and it’s easy for them to communicate with their leadership,” the mayor told Syria Direct, speaking on condition of anonymity for security reasons.

“There are villages that don’t consider IS enemies,” he added. “These sleeper cells find a popular base to help keep themselves hidden—locals either like them, or they fear them.”

The SDF’s focus on the battle for Baghouz drew its forces away from patrolling other areas under its control in Deir e-Zor and Raqqa, the mayor says, making movement and activity there “risk-free.”

Alleged IS attacks in eastern Syria are not limited to SDF targets alone, says Self-Administration Interior Minister Barakat, adding that the militants are in fact striking “diverse targets.”

“The [IS] operations are not particularly precise,” Barakat told Syria Direct. “The important thing [for IS] is to cause fear and panic among people, so they strike both civilians and military personnel.”

It is a sentiment echoed by the mayor in Deir e-Zor. “It’s killing for the sake of killing," he said. "There’s no differentiation between civilian, politician or soldier.”

Fear of more violence is palpable in many formerly IS-held areas in eastern Syria, according to Omran Ahmad, a resident of rural Deir e-Zor province.

“Not a day goes by without us hearing about a new assassination,” Ahmad, who asked his name and precise location be withheld, told Syria Direct. “These [IS] operations make the region unstable.”

“People don’t want to rebuild their homes or restart their lives here [fearing more violence]. It’s gotten to the point that people stay home and don’t go out at night, because it’s too unsafe.”