On December 13, a joint US-Syrian patrol was shot by a member of the Syrian security forces near Palmyra, a city in central Syria once controlled by the ISIL (ISIS) group.
Two American soldiers and an interpreter were shot and four people were wounded, before Syrian forces killed the gunman.
In the wake of the attack, US and Syrian officials linked the attacker to ISIL, which once controlled vast areas of Syria and Iraq, and vowed to retaliate.
The incident highlights the growing cooperation between the United States and Syria against ISIL, especially after Damascus joined the US-backed coalition against the group in November.
While it is still unclear whether the attacker was a member of ISIL or another group opposed to US-Syrian relations, analysts say cooperation between the two countries is strong and growing.
“The Syrian government is responding very strongly to countering ISIL following US requests to do so, and it is worth noting that HTS [Hayat Tahrir al-Sham]before he was in government, he had a long-term policy of fighting ISIL,” Rob Geist Pinfold, an international security scholar at King’s College London, told Al Jazeera, referring to former Syrian President Ahmed al-Sharaa’s group.
“That [HTS] he did it in Idlib and cracked down on insurgents and cells, and this is more of a continuation of that policy.”
A spokesman for Syria’s interior minister, Noureddine al-Baba, told Syrian Al-Ikhbariah television that there was no direct chain of command for the gunman within Syria’s internal security forces and that he was not part of the force tasked with escorting US forces. Investigations are underway, he added, to determine whether he had direct ties to ISIL or adopted a violent ideology.
ISIL strikes down
In May 2015, ISIL took over the city of Palmyra from the former Syrian government.
Famous for its Greco-Roman ruins, the city bounced back and forth between regime forces and ISIL until the group was expelled in 2017.
In May 2017, the US-led coalition also forced the group out of Raqqa, which ISIL had declared the capital of its so-called caliphate three years earlier.
Many surviving ISIL fighters were imprisoned in al-Hol and Roj camps in northeastern Syria, controlled by the US-backed Syrian Democratic Forces (SDF). Others escaped to the Syrian desert around Palmyra, from where they occasionally launched attacks.
When former Syrian President Bashar al-Assad’s regime fell on December 8, 2024, analysts said ISIL fighters used the ensuing chaos to reach various cities across the country. In June, the group launched an attack on a church in Damascus that killed at least 25 people.
Samy Akil, a fellow at the Tahrir Institute, said recent estimates put ISIL’s workforce in Iraq and Syria at between 3,000 and 5,000 fighters.
But experts told Al Jazeera that coordination between Damascus and Washington had improved over the past year and pointed out that Syria’s security forces had foiled several ISIL attacks thanks to information provided by the US.
“Ahmed al-Sharaa’s new government is determined to fight the group, and unlike the Assad era, al-Sharaa’s government receives regular information from US intelligence and probably other forms of US support. That’s a pretty powerful combination,” Century International researcher Aron Lund told Al Jaze Syria.
This collaboration has seen a drop in ISIL attacks in Syria, according to a report by Karam Shaar Advisory. ISIL launched an average of 63 attacks per month in 2024, while in 2025 that number dropped to 10, according to the report.
“Since HTS arrived in Damascus, collaboration [with the US] it has become much easier,” Jerome Drevon, a senior analyst at the International Crisis Group, told Al Jazeera.
Structural defects
After the fall of the Assad regime, there were questions about how security would be provided. The few thousand HTS members who previously controlled only Idlib in northwestern Syria would not be enough to impose security across the country.
Syria’s security forces have embarked on a major recruitment drive, bringing in tens of thousands of new recruits to join many of the existing former opposition battalions that have been incorporated into the state’s new security apparatus.
With such a large recruiting campaign, analysts said, vetting was a difficult task.
“The Palmyra attack points to structural flaws rather than a simple one-off event. The integration of former factional fighters and the rapid recruitment of new ones has produced uneven vetting and surveillance, compounded by an environment permissive for radical views, allowing infiltration to persist,” Nanar Hawash, the International Crisis Group’s senior Syria analyst, told Al Jazeera.
“Together, these factors blur early warning signs and create room for hidden threats, increasing the risk of repeated attacks.”
Analysts said they expect Syrian security forces to improve the vetting process over time. Meanwhile, another attack like the one on December 13 was possible and could damage US confidence that the al-Sharaa government can provide security in Syria.
“It may happen again because of the sheer numbers [of new recruits]but over time, the government will up its game and be more thorough in preventing this from happening again, because there will be consequences,” Drevon said.
“We should be careful about generalizing based on one attack, which may be a one-off. But if it happens again, it could change the perception of the Syrian government.”
What does ISIL want?
As for ISIL, analysts said the group’s priorities have changed since the fall of al-Assad.
“What we are seeing now is that ISIL is trying to test the borders and carry out attacks knowing that it cannot gain territorial control,” Akil said.
“It aims to destabilize and stay relevant.”
“ISIS cannot hold cities or topple governments. But it doesn’t need to. Its strength lies in destabilization,” Hawach said. “The Palmyra attack showed that an agent with the right access can kill three US service members and shake a bilateral relationship.”
Analysts said ISIL could destabilize Syria by targeting state security forces, religious minorities – as it did in the Damascus church attack in June – or any outsider on Syrian soil, from US soldiers to aid workers or the UN. The group may also seek to capitalize on tensions between the SDF and Damascus disagreements about how to integrate the first in the state security apparatus.
The SDF also runs the al-Hol and Roj prison camps in northeastern Syria, where many of ISIL’s most hardened fighters and commanders are held. This could prove to be a key target for ISIL in Syria.
“ISIL thrives in these vacuums,” Hawach said.
“It’s a guerrilla insurgency, not a caliphate, but in a fragile state, that’s enough to cause serious damage.”