Several indicators have emerged across Syria this year, pointing to a renewed surge in activity by the so-called Islamic State (ISIS), which remains designated as a terrorist organisation by the United States, the European Union, and numerous Arab and Asian countries. The group appears to be capitalising on the growing security and political vacuum caused by the gradual withdrawal of US forces and the declining international focus on counter-terrorism efforts.
This raises an urgent question: are we witnessing the early stages of ISIS’s return to prominence, or merely the aftershocks of a post-war phase?
According to The Wall Street Journal, ISIS has carried out more than 117 attacks since the start of 2025 in Deir ez-Zor, Raqqa, and the Syrian Desert – up from 73 attacks in 2024. The report identifies Deir ez-Zor as the organisation’s primary base of operations, where roughly 3,000 fighters are now concentrated.
The newspaper noted that the United States began scaling back its military presence in Syria in April, withdrawing around 500 of its 2,000 troops, mainly from bases in Deir ez-Zor, and transferring some facilities to areas under the control of the Kurdish-led Syrian Democratic Forces (SDF).
Goran Tal Tamer, an SDF commander, told reporters that the drawdown “has inspired the organisation to revive its former activity. Civilians in north-east Syria are suffering from worsening insecurity and chaos, which creates fertile ground for the group’s return.”
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Fragility and Vacuum
Syrian political analyst Darwish Khalifa told +963 that the current climate of instability makes Syrian society more vulnerable to infiltration. This fragility – compounded by security and political turmoil, social fractures, and rapid economic decline – has allowed ISIS to reactivate its networks and increase its attacks by about 60 per cent compared with last year. Khalifa described the uptick as “notable”, given that the group lost its last stronghold in north-east Syria six years ago.
However, Khalifa does not view the escalation as part of a long-term strategy to destabilise the region. Rather, he sees it as a wave of retaliatory strikes against former rivals, carried out through hit-and-run tactics that enable fighters to strike swiftly and withdraw before facing retaliation.
Jordanian researcher Hassan Abu Hanieh, an expert on extremist movements, told +963 that discussions about ISIS’s potential comeback remain highly relevant. “All international intelligence assessments – whether from the UN or specialised research centres – warn that the risk of resurgence remains. The possibility of ISIS returning is always on the table,” he said.
He added that the region has entered a new geopolitical phase since the fall of Assad, with shifting regional dynamics following the events of 7 October. “Counterterrorism no longer ranks as a top global priority. Unlike the post-9/11 era, today’s world powers – the US, Russia and China – are focused on great-power rivalries. This has weakened counter-insurgency strategies and opened space for groups like ISIS to reorganise.”
Warnings of a Return
Could ISIS regain its former strength? Khalifa believes that ongoing tensions could indeed pave the way for a gradual, more structured resurgence of terrorist activity, particularly in the absence of genuine political progress or lasting stability. “Extremist organisations thrive in fragile environments,” he said. “They recruit from the angry and marginalised, using instability as fertile soil for expansion. This demands a serious international response that combines pre-emptive security measures with social and economic de-radicalisation efforts.”
He cautioned, however, that any military or security action must be anchored in a clear political framework that recognises Syria’s complex reality and prevents the country from sliding into renewed cycles of violence.
Abu Hanieh pointed to past precedents: “During the US occupation of Iraq, it was thought that ISIS had been wiped out after 2009–2010. But the group made a ferocious comeback in 2011, stronger than before. The same pattern could repeat itself – possibly even more powerfully than in 2013–2014, when ISIS controlled vast areas of Iraq and Syria.”
The danger, he warned, persists. “ISIS remains highly adaptive, capable of shifting strategies and exploiting geopolitical rifts. Since losing its final pocket in Baghouz in 2019, it has evolved into a decentralised network of small, mobile cells operating across multiple regions. Estimates of its strength vary between 3,000 and 10,000 fighters – but its resilience and ability to recruit are far more concerning than its numbers.”
The International Void
Abu Hanieh explained that a combination of international shifts, regional sanctions, the absence of reconstruction, continued tensions with Israel, and political unrest in Iraq all create favourable conditions for ISIS to return. “Weak regional coordination and US hesitation between staying and leaving keep the door open for the group,” he said.
He noted that declining Iranian influence and rising Turkish–Israeli competition have produced a state of geopolitical uncertainty, allowing ISIS to rebuild its networks across Syria, Iraq, and other security voids. “This is not a hypothetical scenario,” he warned. “It is a realistic and increasingly likely outcome unless comprehensive strategies are implemented to address the root causes of extremism and violence.”
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Is the US Really Leaving?
Even with these underlying factors, one key question remains: is the United States truly leaving Syria – and could that withdrawal, if it happens, be the trigger for ISIS’s return?
Wael Alwan, a researcher at the Jusoor for Studies, doubts it. Speaking to +963, he said: “Although US troop numbers have decreased in recent years, Washington’s operations in Syria do not require a large presence.”
He added that internal assessments submitted to the US administration indicate that maintaining forces in Syria is relatively low-cost in both logistical and security terms. “The American presence – through bases and direct involvement – continues to yield significant political and security benefits for Washington despite the limited troop numbers,” he said.
Alwan expects the United States to focus instead on withdrawing from Iraq, alongside efforts to dismantle the Popular Mobilisation Forces there. “That scenario could create a larger opening for ISIS in Iraq rather than Syria,” he said.
He concluded that while ISIS may attempt to revive its networks in Syria, recent internal and external arrangements – particularly those bringing the Syrian government into cooperation with the international coalition – will likely strengthen efforts to suppress any resurgence. “Coordination between the SDF and the transitional Syrian government, mediated by the United States, will further restrict the group’s movement,” he said.
“The local actors alone cannot contain ISIS,” Alwan warned. “Only a joint US-backed approach – linking government forces with the SDF – can effectively curb the organisation’s ability to rebuild.”
