PARIS, Dec 10, 2024 (BSS/AFP) - What remains of the Islamic State (IS) group in Syria could gain new life after Bashar al-Assad's fall, potentially claiming territory and freeing its fighters in the Kurdish-controlled northeast.

IS has long flourished in conditions of war or uncertainty, often on the territory of failing states.

Its fighters are for now holed up in small cells spread across the eastern Syrian desert -- with their survival already marking a win in the face of the defunct Assad leadership's weak grip on the region.

A chaotic political transition following the bloody half-century of the dynasty's rule and 13 years of civil war could offer the scattered jihadists benefits.

"Chaos and anarchy will inevitably be a boon to the Islamic State, which has been biding its time, slowly and steadily rebuilding its networks throughout the country," said Colin Clark, research director at the New York-based Soufan Center.

Apparently scenting danger in the light of Assad's ouster at the weekend, US Central Command -- responsible for operations in the Middle East -- said Sunday it had launched air strikes against more than 75 IS targets.

IS's own official weekly Al-Naba wrote in its latest edition that it would accept no new government in Damascus unless the group itself was in charge.

Unlike the IS "caliphate" that stretched across parts of Iraq and Syria from 2014-19, the aim of the separate Islamist rebels who ousted Assad "is to create a civil and democratic state, far removed from its project of a state built on sharia", or Islamic law, said Laurence Bindner, co-founder of the JOS Project which tracks extremist propaganda online.

By contrast, IS jihadists "present themselves as the only viable alternative that would impose respect for religious principles while opposing foreign interests", Bindner told AFP.

She pointed out that IS harshly criticises the victorious rebels' appeals for peaceful coexistence with religious minorities such as Alawites, Yazidis and Christians, which represent "the opposite of its radical vision".

- Afghan style -

IS is widely seen today as a shadow of its former stature as a centralised organisation able to coordinate its branches across the Middle East and Africa and launch attacks there and in the West.

But many experts have for years warned against consigning the group and its "brand" prematurely to the history books.

It claimed just 121 attacks across Syria in 2023, down from 1,055 in 2019 -- although the figure has increased this year, wrote Aaron Zelin of the US-based Hudson Institute think tank.

"There has been significant evidence suggesting that the Islamic State has purposefully underreported its claims in Syria to make it appear weaker than it actually is," Zelin added.

Even after the fall of the "caliphate", IS "has continued to try and tax individuals at 2.5 percent... in different parts of eastern Syria", he added.

The group also has long experience harassing authorities -- a practice it will likely continue even if power is claimed by the leading rebel group Hayat Tahrir al-Sham (HTS), which itself has a radical Islamist ideology.

"IS will try to bite as much territory and gains as possible from HTS if it controls Syria," said Yoram Schweitzer, a former Israeli intelligence officer and now researcher at the Tel-Aviv-based Institute for National Security Studies.

The strategy would match "what ISKP did when the Taliban took control" of Afghanistan, he added, referring to attacks by IS's Afghan branch following the US withdrawal from Kabul in 2021.

- Vast prison camps -

Whatever authority ends up controlling Damascus, IS's reaction is likely to be the same.

"They will look at anyone controlling the power... as a basic, fundamental enemy that they should operate against," Schweitzer said.

One weak spot expected to swiftly draw IS's eye is the string of overcrowded, lightly guarded camps in the Kurdish zone where tens of thousands of former IS fighters, women and children have been held for years.

The group already staged a successful breakout from the Ghwayran prison camp in January 2022. But top of the target list would likely be the gigantic Al-Hol camp.

"They will try to take advantage of the situation and try to either break in the jail or try to assist those in the jail to break out", Schweitzer said.

He pointed to Kurdish authorities' trouble maintaining order in the camps in recent years, even as they come under attack from Turkish forces who in turn label the Kurds as "terrorists".

One key factor in IS's success or containment will be American willingness to maintain its roughly 1,000 troops on the ground in Syria to fight IS and keep Ankara from striking the Kurds.

For US president-elect Donald Trump, fighting IS in Syria is "part of his legacy" from his 2016-2020 first term, Soufan Center expert Clarke told AFP.

"I don't think he'd want his legacy to be undone by withdrawing US troops from Syria and giving Turkey a green light to go after the Kurds," he said.

"You could end up with a situation where IS was the main beneficiary."