Erbil, Iraq - The US completed its planned troop withdrawal from Iraq by 30 September, with the last of the remaining anti-Islamic State (IS) coalition troops leaving Iraqi Kurdistan’s capital, Erbil, ahead of that deadline.
The withdrawal, however, has renewed anxieties in Iraq that IS could exploit the inevitable power vacuum and regional crises to reorganise and regroup, threatening the region and its peoples once again.
In late September, veteran Kurdish leader Masoud Barzani warned that the withdrawal reopens the risk of another IS resurgence. He recalled how the previous 2011 American withdrawal led to the infamous IS invasion of Iraq in mid-2014. “I fear the same scenario will happen,” he said.
Barzani isn’t the only one concerned about IS. Former Iraqi Interior Minister Baqir Jabr, a veteran Shia politician, claimed in early October that IS remnants in Syria have increased to as many as 10,000 fighters since the former regime of Bashar Al-Assad collapsed in December 2024.
IS initially seized territory in Syria and expanded by invading northern Iraq in June 2014, declaring a caliphate on those vast swathes of territory it conquered and symbolically dismantling the Iraq-Syria border.
While a restoration of that self-styled caliphate isn’t imminent today, analysts warn that multiple factors must be addressed to prevent a significant IS resurgence.
Obstacles
“IS is definitely trying to make its presence known in Iraq with the US withdrawal, but it is still small and relegated to mostly rural areas of northern Iraq with very little support,” Joel Wing, author of the Musings on Iraq blog, told The New Arab.
“There are no signs that Sunni Arabs are backing the group once again,” he said. “During the war, the government forces carried out widespread Sunni cleansing and still occupy many Sunni areas, making it far too costly for people to back the insurgents again.”
Mohammed A. Salih, a non-resident senior fellow at the Foreign Policy Research Institute, noted that conditions in Iraq and Syria are markedly different from those in 2012-14.
“Iraqi Sunnis participate in the political process despite ongoing grievances, while security forces are more capable, particularly with the presence of the ideologically driven Popular Mobilisation Forces,” Salih told The New Arab.
“Syria also has a generally functioning government rather than a full-scale civil war.”
The PMF consists of several mainly Shia militias mobilised in 2014 to help combat IS. Many powerful Iran-backed groups operate within the state-sanctioned paramilitaries and have refused recent efforts by incumbent Iraqi Prime Minister Ali al-Zaidi to disarm them.
Despite the significantly different circumstances between today and 2014, Salih still sees a significant risk of an IS resurgence. Stopping it will very much depend on continued support from the US-led coalition and security cooperation between Iraqi and Kurdish forces.
Across the border, Syria's new security forces must also show the “willingness and capacity” to contain IS.
“Ideological overlap between some elements of Syria’s security apparatus and IS could also create openings, especially amid economic hardship and growing public frustration over the government’s approach to dealing with Israel,” Salih said.
To Iraq’s east, any collapse or substantial weakening of the regime in Iran could undermine Iraq’s ruling Shia elite, potentially creating opportunities for IS.
“Some regional actors might also be tempted to support a Sunni insurgency if Iran-backed Iraqi militias continue attacking neighbouring countries, further increasing the risk of instability,” Salih said.
Security gaps
In 2014, the Iraqi Security Forces (ISF) infamously failed to prevent a comparably small number of IS militants from swiftly seizing Mosul.
Today, Wing believes the ISF are “far more competent,” noting that they are no longer reactive and are “mostly carrying out pre-emptive raids and operations”.
After losing all of the territory it captured in Iraq in 2017, IS remnants were still able to operate within security gaps in the disputed territories between federal Iraq and Iraqi Kurdistan, such as Kirkuk.
IS benefited from the lack of cooperation between the ISF and the Kurdish Peshmerga, particularly in the aftermath of Iraq’s forceful seizure of Kirkuk from the Peshmerga in October 2017.
Iraqi lawmaker Mazen Gharib warned this October that the group is once again doing this following the coalition’s withdrawal, pointing to increased movements in Kirkuk province and the existence of “active detachments.” On 10 October, Iraq’s security forces and IS clashed in Kirkuk’s Hawija district.
According to Wing, the gap between the Iraqi forces and the Peshmerga continues to be a security concern in Iraq.
“There are some areas where the space between the two forces is quite large, and IS has exploited this for years,” he said.
“The problem is this is in the disputed territories and the Kurds want to move back into them after they were forced out following the 2017 Kurdish independence referendum and Baghdad does not want them to return,” he added.
“This dispute has resulted in the security gap between the two sides.”
Sectarian fault lines
FPRI’s Salih concurs that the ISF is more prepared than before. “At the federal level, the presence of the PMF, as an ideologically driven and predominantly Shia force, has strengthened the ISF’s overall capabilities,” he said.
“However, effective coordination between federal and Kurdish forces remains critical to denying IS the operational space it needs in the disputed territories.”
Security coordination between Iraq and Syria is also “hugely important” for containing IS. Such cross-border cooperation is essential since the “predominantly Sunni Arab borderlands” between them have served as a “core breeding ground and operational hub” for IS for several years.
Wing noted that the two neighbours are trying to cooperate on border security for the first time in decades. “How thorough that is remains to be seen, but it can’t do anything but help,” he said.
Still, some of the forces deeply distrust one another. Iran-backed PMF groups entered Syria during the civil war to fight for President Bashar Al-Assad while the former militias that make up the new Syrian armed forces fought against Assad.
“The two definitely don't like each other, but there have not been reports of the two clashing,” Wing said.
“I think with everything else going on in the region such as the Iran war, Prime Minister Zaidi demanding the PMF to disarm, etc., the distaste for the new Syrian government has simply not been a priority.”
Independent Iraqi analyst Lawk Ghafuri noted that while IS was militarily defeated in Iraq in 2017, its ideology was never eliminated.
“Since December 2024, Syria has become an increasingly concerning environment, with foreign extremists, including individuals with IS and al-Qaeda backgrounds, potentially embedded within the new security structures,” Ghafuri told The New Arab.
“The presence of the PMF in Iraq and hostile forces across the Syrian border creates a dangerous sectarian fault line.”
Islamic State prisoners
Iraq presently holds thousands of suspected IS militants and their families in its prisons. Thousands of them were airlifted by the US military from Syria in January, including from the infamous al-Hol camp.
These militants previously attempted a well-planned, coordinated jailbreak in Syria’s Hasakah in January 2022, which took local Kurdish-led security forces more than a week to suppress.
Human Rights Watch released a report in early September charging that these detained IS suspects in Iraq face abuse, unfair trials, and executions.
The report also noted that dozens of countries are stalling on repatriating their national suspects, pledging aid instead. Baghdad rejected a Syrian request to repatriate 4,000 Syrian suspects in Iraqi custody, declaring that any of those Syrians who committed crimes in Iraq will be tried there under Iraqi law.
FPRI’s Salih argued that it is critically important for countries with nationals among the IS prisoner population in Iraq to repatriate them, noting that Iraq is already “overwhelmed by the sheer number” of these inmates.
“Iraq should not be treated as a dumping ground for unwanted IS elements and prisoners,” he said.
“In the event of major instability or chaos in Iraq, particularly as a consequence of the Iran-US-Israel war, these prisoners could become a readily available pool of battle-hardened and highly motivated manpower for IS,” he added.
There are concerns in Iraq that these prisoners could return to the battlefield in the event of a prison break, or if regional tensions spill into Iraq, Salih notes.
“That said, it is important that other countries repatriate their nationals held among IS prisoners and help alleviate some of the enormous burden Iraq is shouldering.”
Ghafuri pointed out that the US-Iran war has undoubtedly shifted regional attention further away from counterterrorism, giving IS elements a potential “opportunity to regroup” and prepare for their next phase.
“IS may no longer face the same international military pressure, while regional governments are preoccupied with Iran, oil, and wider geopolitical rivalries,” he said.
“The greatest danger is not simply that IS could return, but that the regional conditions that once enabled its rise are beginning to re-emerge.”
Paul Iddon is a freelance journalist based in Erbil, Iraqi Kurdistan, who writes about Middle East affairs.
Follow him on Twitter: @pauliddon
Edited by Charlie Hoyle