Islamic State has shown renewed vigour in Syria, attracting fighters and increasing attacks, according to the United Nations and US officials, adding to the volatility of a country still reeling since the fall of president Bashar al-Assad.
The group is still nowhere near as strong as it was a decade ago, when it controlled eastern Syria and a large part of northern Iraq, but there is a risk, experts say, that Islamic State, also known as Isis, can find a way to free thousands of its hardened fighters who are held in prisons guarded by US-backed Syrian Kurdish forces.
A serious resurgence of Islamic State would undermine a rare moment when Syria seems to have a chance to move beyond a brutal dictatorship. But it could also reverberate more broadly, spreading instability through the Middle East. The extremist group once used Syria as a base to plan attacks on the country’s neighbours and in Europe.
Between 9,000 and 10,000 Islamic State fighters and about 40,000 of their family members are detained in northeastern Syria. Their escape would not only add to the group’s numbers but also provide a propaganda coup.
“The crown jewel for the Islamic State is still the prisons and camps,” said Colin Clarke, the head of research for the Soufan Group, a global intelligence and security firm.
“That’s where the experienced, battle-hardened fighters are,” he said. “In addition to whatever muscle they add to the group, if those prisons are open, the pure propaganda value” would serve the group’s recruitment efforts for months.

Top US intelligence officials last month presented to Congress their annual worldwide threat assessment, concluding that Islamic State would try to exploit the end of the Assad government to free prisoners and to revive its ability to plot and carry out attacks.
The US announced late last year that its military had roughly doubled the number of its troops on the ground in Syria, to 2,000, and its many strikes on Islamic State redoubts in the Syrian desert in the last few months appear to have tamped down the immediate threat.
But president Donald Trump has expressed deep scepticism about keeping US troops in the country, and a confluence of other developments in Syria has alarmed experts who say that, taken together, they could make it easier for Islamic State to regroup further.
The US has hopes that the new Syrian government, led by a onetime al-Qaeda affiliate, Hayat Tahrir al Sham, will become a partner against a resurgent Islamic State. The initial signs were positive, with the group acting on US-provided intelligence to disrupt eight Islamic State plots in Damascus, according to two senior US military officials who spoke on the condition of anonymity to discuss sensitive operations.
But sectarian-driven violence last month, in which hundreds of civilians were killed, showed the government’s lack of control over some forces nominally under its command, and it is unclear how much bandwidth it will have to fight Islamic State.
The Islamic State, a Sunni Muslim insurgent group, traces its beginnings to al-Qaeda in Iraq, where it was defeated by local militias and US troops. Its fighters rebranded as Islamic State and exploited the chaos of Syria’s civil war to seize vast swathes of territory and return to Iraq.
It gained notoriety for kidnappings, sexual enslavement and public executions, and orchestrated or inspired a series of terrorist attacks across Europe. The group had largely been routed more than five ago by a combination of the Kurdish-led Syrian Democratic Forces in northeastern Syria and US troops. But by early 2024, the Assad regime was increasingly on the defensive; its Iranian and Russian allies were stretched by conflicts elsewhere; and Syria’s Kurds were forced to divert troops to battle Turkish attacks.
But although it no longer holds much territory, the Islamic State group is still spreading its radical ideology through clandestine cells and regional affiliates outside Syria and online. Last year, the group was behind major attacks in Iran, Russia and Pakistan.
In Syria, according to a US defence department official who spoke anonymously to discuss information that has not yet been released publicly, the group claimed 294 attacks in 2024, up from the 121 it claimed in 2023. The UN’s Islamic State monitoring committee estimated about 400 attacks, while human rights observers in Syria said the number was even higher.
Attacks so far this year appear to have slowed, according to human rights groups and US military officials – in part because of the recent US bombing campaign targeting Islamic State fighters – but it is still relatively early in the year, and the situation hangs on a knife’s edge.
Aaron Zelin, a Washington Institute fellow who has tracked Islamic groups’ activities and propaganda for more than 15 years, said the unrest facing the new government from remnants of the Assad regime and incursions by Turkey into Syria were its biggest challenges right now. But he warned that Islamic State added yet another threat.
“One big attack in Damascus against foreigners or expats, and everybody’s going to change how they view it, so we need to be cautious,” he said.

The concerns over a possible prison escape by Islamic State detainees have been heightened by ongoing violence in the northeast. The detention centres in northeastern Syria are guarded by the Kurdish-led fighters, the Syrian Democratic Forces, who also help guard the nearby camps that hold Islamic State family members. But those forces have been distracted by attacks from Turkish-backed militias.
Turkish authorities view the Kurdish-led fighters as the Syrian branch of Kurdish separatists in Turkey who have waged a 40-year battle against the Turkish government. Turkey sees them as terrorists.
The prisons have already proved to be a concern. In 2022, nearly 400 Islamic State-linked prisoners escaped during an Islamic State assault on a prison in the city of Hasaka. At the time, US Special Operations forces helped the Syrian Democratic Forces get control of the situation.
Since then, US intelligence on potential jail breaks has helped the Syrian Democratic Forces disrupt other plots before they happened, one of the senior US officials said.
In Al Hol, the largest camp where Islamic State women and children have been held for years, the extremist group has been testing the boundaries. In a recent report, a UN committee said the chaos surrounding the fall of Assad allowed some Islamic State fighters to escape the camp, although it was not clear how many.
If the Syrian Kurds are weakened, “there is no question that it will create a vacuum,” said Kawa Hassan, an Iraqi analyst and a non-resident fellow at the Stimson Center, a non-partisan organisation in Washington. “And only the Islamic State thrives in a vacuum.”
– This article originally appeared in The New York Times.
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