How dangerous are Syria's foreign fighters really?

He's a traitor to the cause, an infidel and a "slave" who "groveled" before US President Donald Trump. In the latest edition of its weekly newsletter, the extremist group known as the "Islamic State," or IS, didn't hold back how it really felt about Syria's new interim president, Ahmad al-Sharaa, and his meeting with Trump last week.

In fact, this sort of enmity between the IS group and the rebel group al-Sharaa once led, Hayat Tahrir al-Sham, or HTS, is not new.

Between 2012 and 2013, HTS was part of the so-called Islamic State group before switching to ally itself with al-Qaeda. Then after cutting ties with al-Qaeda in 2016, HTS spent almost a decade fighting IS in parts of the country it controlled. So the criticism of al-Sharaa's more moderate, expedient political course is not unexpected.

But there is another interesting aspect to the al-Naba text. The IS group also called on foreign fighters in Syria to defect from the current government led by al-Sharaa. Foreign fighters upset at al-Sharaa's diplomacy with the US should join IS, the group exhorted.

The al-Naba text and al-Sharaa's meeting with Trump has refocused attention on one of the interim government of Syria's toughest problems: What to do about the presence of foreign fighters in the country.

During last week's meeting, the US president pressed al-Sharaa to "tell all foreign terrorists to leave Syria" making it one of the conditions for sanctions relief. French and German envoys have made similar statements and in general, the fear is that Syria could become a haven for groups with extremist ideologies that then become active internationally.

Who are Syria's foreign fighters?
It's hard to know exactly how many foreigners were fighting alongside HTS. There could be anywhere between 1,500 and 6,000, with many experts suggesting it's most likely a number in the middle of that range.

The largest group is comprised of Uyghurs, many of whom are involved with the Turkistan Islamic Party, from central and East Asia, including China.

Other fighters are from Russia and other former Soviet states, the Balkans, France, the UK, Turkey and various Arab countries, among others.

Most came to Syria early during the country's civil war in response to calls from the IS group, which was trying to establish a caliphate at the time. After it broke ties with both IS and al-Qaeda, some foreigners left HTS, while others stayed.

Late in 2024, during the HTS-led campaign that ousted Syrian dictator Bashar Assad several groups of foreigners, including Uyghurs and Chechens, apparently played an integral part in the campaign's success.

Al-Sharaa has said they should be rewarded for their help and in January, a number of foreign fighters were appointed to senior positions in the new Syrian military, a decision that caused some controversy.

It's hard to say how important the foreign fighters are to Syrian security forces now, Aaron Zelin, an expert on HTS and a senior fellow at the Washington Institute told DW, "because there are obviously a lot more Syrians than foreigners."

But some are more important than others, he noted. For example, fighters from the Uyghur contingent now act as something of a personal security force for al-Sharaa. "They're essentially the ones protecting him because he trusts them, they're viewed as brothers in arms from the fight against Assad," Zelin said.

A Syrian refugee now living in Germany told DW he had met a number of foreign fighters while combatting Assad regime forces in the Syrian city of Aleppo. "Some were good, some not so good," he said, requesting anonymity for security reasons. "They were very focused on fighting and a lot of them had a Salafist mindset," he noted, referring to the conservative, fundamentalist Sunni Muslim movement. "They wanted to go where the battles were."

But, added the former fighter, "the ones that stayed now have families in Syria. So personally, I'd give them a chance — especially because if we expel them, we also expel the women and the children. Anyway, don't forget, there are also a lot of Syrians who would share at least some of that [religious] mindset."

How dangerous are the foreign fighters?
Foreign fighters with a more hardline religious bent have been accused of taking part in recent violence against Syrian minorities. They have also been blamed for policing female dress and social customs in Syria's bigger cities.

Until very recently HTS was still positioning itself as a "defender of Sunni Islam," Orwa Ajjoub, a research analyst and expert on Syria, explained in a text for the Italian Institute for International Political Studies in March. But after the fall of the Assad regime, the group set a more liberal course, he wrote.

"This abrupt change in narrative presents a significant adjustment for the rank-and-file," Ajjoub explained. "This transition may be challenging for fighters used to a narrower, sectarian viewpoint. Many HTS fighters, having never left the conservative environment of Idlib, are now encountering less conservative communities in Damascus."

People stand next to a illuminated Christmas tree decorated with the "revolutionary" Syrian flag in the city of Aleppo, Syria.

Joining the 'Islamic State'
"If HTS continues its trend toward relative moderation such as tolerating unveiled women, alcohol sales and participation in a Western-style political process … hardline elements within HTS, particularly foreign jihadis, could break away, defect to, or cooperate with ISIS or al-Qaeda," Mohammed Salih, a senior fellow with the Foreign Policy Research Institute, a Philadelphia-based think tank, warned in January.

But Zelin said he was skeptical about foreign fighters in Syria posing "any large-scale threat."

The ones who felt HTS was no longer hardcore enough for them have most likely already left, he noted, and many of the less radical foreign fighters who stayed are highly disciplined. For years now, al-Sharaa has also tried to sideline, arrest or expel any foreign fighters who resisted the group's new course.

Of course, individual foreign fighters could still commit crimes or cause problems, he said. "But the larger threat comes from foreign fighters already inside the "Islamic State," the ones continuing to fight a low-level insurgency in eastern Syria, as well as those detained in northeast Syria by the SDF," he explained, referring to detention camps run by Syrian Kurds.

What next for foreign fighters?
After al-Sharaa's meeting with Trump, there were rumors that Syrian security forces had raided foreign fighter bases in Idlib. But local observers say it's unclear whether these were just rumors, political theatre or really happened.

A major crackdown seems unlikely. Members of Syria's new government have argued foreign fighters don't pose any threat to other countries, there's too few of them to significantly impact the new Syrian army and that anyway, they're loyal to al-Sharaa's new administration. Experts say integrating them into new Syrian security forces may actually be the best way of dealing with them.

Still, as Zelin concluded, "of all the requests made by the US, this is probably the hardest one for Syria. I don't think that they really want to give up the foreign fighters unless, for example, they're doing something against the law."