In late November, intense fighting broke out in Aleppo, Syria. The offensive, which has spread to northern Hama, is led by a proscribed terrorist group, namely Hayat Tahrir al-Sham (HTS), an Islamist rebel organization based in northwestern Syria’s Idlib province. Aleppo now appears to be under the control of HTS and its allies, with photographs and video circulating that suggest these groups have gained substantial control over much of the city, including the airport. In response, Syrian and Russian forces have launched air attacks to regain control of the city and fortify the position of Syrian Arab Republic forces, which are also on the defensive in northern Hama. An Iranian delegation has landed in Damascus for urgent dialogue with President Bashar al-Assad and to shore up support for the government. For anyone who thought the conflict in Syria was over, and has prematurely celebrated the “defeat of ISIS,” a reckoning is due.

For months, commentators who closely watch Syria have been warning about the mounting ferocity of ISIS attacks, as well as the growing organizational capacity of proscribed groups and affiliated organizations in the region. While some view HTS as a primarily “localized” force, with limited territorial reach, the recent fighting demonstrates that the group retains the ability to reignite the long dormant conflict across northern Syria. Many of us have long argued that the so-called defeat of ISIS was prematurely declared, not least because there has been no reckoning with the causes of the ongoing conflict(s), no fundamental accounting for the political instability that defines life in northeast and northwest Syria, and no willingness by responsible States to address tough questions, including a negotiated settlement among parties, or even a partial settlement. And while ISIS appears to be playing a limited role in the current battles in Aleppo and Hama, it remains poised to capitalize on the ongoing insecurity, even as its rival terrorist organizations, such as HTS, surge.

As other regional wars and bombardments, including the conflict and civilian catastrophes in Gaza and Lebanon, have garnered headlines, violence has been brewing in the background in Syria. Armed groups have tenaciously consolidated their forces and control over territory, but international and regional powers have demonstrated little desire to do anything more than maintain a certain status quo between all the parties on the ground following the fall of Raqqah in 2017.

The U.S.-backed Syrian Democratic Forces (SDF) have been left to manage a massive detainee population in multiple prisons and detention facilities, as States including Canada, Australia, France, the United Kingdom, Tunisia, the Maldives, Trinidad and Tobago, and Egypt, as well as other nations, prevaricate on their fundamental human rights and security obligations to other States. Nowhere is the unsustainable status quo more evident than in the ongoing failure of these States and others to return their third country nationals from detention sites in northeastern Syria.

When I visited that territory in July 2023, months after an unsuccessful but deadly attack on Al Hasakah prison, it was clear that “out of sight” should not be “out of mind.” For States that claim to be concerned about preventing violent conflict and want to stop another regional conflagration, the failure to address these prisons and detention facilities is not just grim human rights practice, but also myopic long-term security thinking. Terrorist groups such as ISIS have repeatedly targeted such facilities, which serve as incubators for extremism and house experienced fighters looking to return to the battlefield. Prison breaks have fueled ISIS’s rise in the past and could easily fuel its territorial gains once again, as thousands suspected of having an affiliation with ISIS remain in SDF facilities. My estimate in July 2023, was that over 73,000 men, women and children were detained across multiple facilities.

Other tough issues that must be addressed in the short and medium term include systematically making accountability for serious human rights and humanitarian law violations committed throughout the course of the Syrian civil war a reality. Thorny questions of managing ongoing amnesty are now intermingled with accountability, to which one can add the horror of scalar disappearances. Of course, these problems are exacerbated by an ongoing humanitarian crisis in which Syrian civilians lack access to water, food, and a basic health infrastructure – all of which compounds misery and makes (other) violent alternatives to the status quo palatable.

When these basics are not addressed violent extremism follows, and the fertile ground that exists for violent armed groups deepens. Anyone who knows this region is probably not surprised by the events of recent days in Aleppo and the outskirts of Hama. Rather we are asking how many more signals are needed such that the Syrian conflict is no longer ignored, and diplomatic efforts involving all the parties are pursued in earnest. If the international community wants to resolve this conflict, and prevent future ones, it will have to fundamentally address the conditions that produce it.

In late 2019, then President Donald Trump made an impulsive decision to withdraw U.S. troops from Kurdish-held territory in northeast Syria. The results included further instability and paved the way for the resurgence of ISIS. The new battles raging in Aleppo and north of Hama are a warning: Syria can no longer be ignored. In particular, the situation of thousands of men, women and children deemed affiliated with ISIS must be resolved. In the weeks ahead, responsible governments should bring their nationals home with urgency, viewing their arbitrary detention not just as an egregious human rights violation, but also as strategically necessary to ensure regional and global security. Parallel to concrete action on detainee returns, States should rekindle mediation and negotiation efforts, pursuing discrete confidence-building measures among all parties.

IMAGE: An anti-regime fighter stands on a road as displaced Syrian Kurds drive vehicles loaded with belongings on the Aleppo-Raqqa highway to flee areas on the outskirts of the northern city of Aleppo which were formerly controlled by the Kurdish-led Syrian Democratic Forces (SDF), after they were seized by Islamist-led rebels on December 2, 2024. On November 27, the Islamist Hayat Tahrir al-Sham (HTS) alliance led a major offensive snatching Syria’s second city Aleppo and dozens of towns and villages from government control, after years of regime gains in successive Russian-backed military campaigns. (Photo by RAMI AL SAYED/AFP via Getty Images)