The "Islamic State" (IS) , also known as the Islamic State of Iraq and Syria (ISIS), has been widely defeated across Syria, but still poses a threat to the nation's peaceful future. This, at least, is the estimation of outgoing US President Joe Biden, whose administration has ordered massive airstrikes against the extremist organization.

The arsenal of military aircraft involved in the campaign is a sign of just how seriously the Biden administration takes the threat. Heavy B-52 bombers have been involved in strikes on central parts of Syria, as were F-15 and A-10 Thunderbolt fighter jets.

On social media platform X, formerly Twitter, the US Central Command said these "strikes against the ISIS leaders, operatives, and camps" in central Syria were "part of the ongoing mission to disrupt, degrade, and defeat ISIS." It reported that it had conducted "dozens of precision airstrikes."

"There should be no doubt — we will not allow ISIS to reconstitute and take advantage of the current situation in Syria," General Michael Erik Kurilla was quoted as saying. "All organizations in Syria should know that we will hold them accountable if them partner with or support ISIS in any way."

"We will help […] ensure stability in eastern Syria, protecting any personnel — our personnel against any threats," Biden said in a statement on Sunday. "Our mission against ISIS will be maintained, including the security of detention facilities where ISIS fighters are being held as prisoners." 

'Islamic State never entirely disappeared'

Middle East expert and political consultant Carsten Wieland said the so-called "Islamic State" never truly left Syria, even if it had been widely defeated.

"There are still various cells, including sleeper cells, in central and eastern Syria," he told DW. "And they certainly do pose a threat." That is particularly serious when there's a power vacuum, he said, adding that he thought the US had made the right decision.

"Now's the time to stabilize the forces that have taken over power in Syria as peacefully as possible, and not to burden them with another front in the form of the 'Islamic State.'"

IS got its start in Iraq

Founded in Iraq in the context of the 2003 US invasion, the "Islamic State" started spreading through Syria in 2012 amid the chaos of civil war. Here, the organization called itself the Al-Nusra Front. Its commander, Abu Mohammed al-Golani, is the same man who now leads the Hayat Tahrir al-Sham (HTS) militia that just overthrew Syrian dictator Bashar  Assad.

From an ideological standpoint, al-Golani had increasingly distanced himself from the Iraqi IS, and the rivalry between the two groups mounted in the subsequent years.

Ongoing attacks against civilians

Weakened by years of civil war, the Syrian armed forces did not have much left to counter the IS. Many soldiers lost their lives in battles and ambushes.

But from 2015, IS — just like the Al-Nusra Front — faced growing pressure from the US military. Their ranks were considerably weakened and they were forced to concede their claims to any territory in 2019. While several military and spiritual IS commanders, known as caliphs, managed to stay in power, the US was repeatedly successful in disabling cells.

Many IS members were imprisoned in northern Syria, where they remain in camps to this day.

Despite all this, several IS cells and camps stayed intact, especially in the Badia desert, along Syria's border with Iraq. Wieland said the cells often carried out attacks on the rural population, especially against those hunting for truffles in the area.

"Several dozen people have been killed," he said. Since other members act as sleeper cells and wait for possible orders, it's almost impossible to definitively destroy the group, he explained.

Al-Golani split from 'Islamic State' possible

In its current state, IS seems unable to spread very far, let alone reestablish control in its former territory. But following the toppling of Assad and the political upheaval, the notoriously brutal terror group might attempt to expand its sphere of influence again. This is why it's currently under such fierce attack.

Commenting on al-Golani's ties with IS, Wieland said it was quite conceivable that the HTS leader had indeed broken with its ideology. "The group reached various deals and agreements with local actors," he said. "That gives me hope for a constructive progression."

He also pointed out that he found it "remarkable that there have been no large massacres or revenge campaigns."

"Under the IS ideology, the past few days would have seen entirely different developments."

This article was originally written in German.

Correction, December 11, 2024: An earlier version of this article misspelled the name of Abu Mohammed al-Golani. DW apologizes for the error.