They were part of Iran's "Axis of Resistance" — Syria-based proxy groups created to defend the former Assad regime as part of Iran's campaign to expand its influence across the Middle East.
The Fatemiyoun Brigade was made up of Afghan Shiites brought in from Iran; the Zainebiyoun Brigade was composed of their Pakistani religious cohorts.
At the height of the Syrian civil war, the two groups fought in major battles, helping Syrian forces to reclaim lost territory from the Islamic State group (IS), including Palmyra and Aleppo in 2016 and Raqqa and Deir ez-Zor in 2017.
But when a coalition of anti-Assad rebels swept the country in recent weeks, most abandoned their posts and fled, according to news accounts and researchers who follow these groups.
"They folded so quickly that central bases that I knew for a fact were surrounded by at least 1,000 of these guys were empty," said Phillip Smyth, who has researched Iranian proxy groups for nearly 20 years.
Their whereabouts remain uncertain. But experts say Iran is unlikely to disband them at a time when Hamas and Hezbollah — two other members of the Axis of Resistance — are reeling from devastating Israeli strikes.
"They need forces like this," Smyth said in an interview, referring to Iran. "They can no longer rely on Lebanese Hezbollah. They can no longer rely on a lot of other regional partners, so I think if we look at this, they kind of have to not only keep it going, but they're going to have to probably develop it in a different way."
Origins
The Fatemiyoun and the Zainebiyoun emerged in the early years of the Syrian civil war as the fundamentalist Sunni IS began threatening the Assad regime and targeting Shiite shrines in Syria and other Shiite sites.
The Fatemiyoun started in 2012 with just a handful of Afghan Shiite volunteers. Some had fought in the 1980s Iran-Iraq war and the 1990s Afghan civil war, while others were living as refugees in Syria.
Initially fighting alongside other pro-Assad militias in Syria, they emerged as an independent group in 2013, largely led by Iranian military commanders, according to Smyth.
The Pakistani Zainebiyoun, the smaller of the two groups, was initially part of the Afghan Fatemiyoun, according to Smyth. But the Pakistanis didn't always "mesh" with the Afghans, so Iran's Islamic Revolutionary Guard Corps (IRGC) decided to split them off, according to Smyth.
Despite initial denials, the IRGC's involvement in recruiting, arming, training and funding the two militias was an open secret, according to researchers.
The IRGC used a combination of incentives and coercion to recruit Afghan refugees and migrants. Undocumented Afghans were offered money and the promise of legal status. Some were pulled out of prisons and were promised that their criminal records would be expunged if they joined the Fatemiyoun, according to Smyth.
Others were religiously and ideologically motivated, determined to defend Shiite shrines against IS. Many Afghans and Pakistanis were recruited from religious seminaries in Iran.
The recruitment effort extended to Afghanistan and Pakistan, where Iran-allied Shiite groups enlisted volunteers, drawing fire from the authorities.
According to Fakhar Hayat Kakakhel, a researcher on militant outfits in Pakistan, many Zainebiyoun members were recruited from Pakistan's Shiite-dominated Kurram tribal district, Gilgit region, southern Punjab and the Hazara population in Quetta.
As the civil war intensified and IS emerged as a potent force, the ranks of the two groups swelled.
In 2015, a news outlet affiliated with the general staff of the Iranian armed forces reported that the Fatemiyoun had been upgraded from a brigade to a division, suggesting it had between 10,000 and 20,000 soldiers.
Smyth estimates their number more conservatively at 5,000 to 10,000. The Zainebiyoun was about half that size with 2,500 to 4,000 fighters, according to Smyth.
Role in Syrian civil war
The two groups played a significant role during the Syrian civil war, serving as key pillars of support for the Assad regime. At various points during the conflict, they operated across nearly all of Syria's governorates, said Muaz Al Abdullah, Middle East research manager at Armed Conflict Location & Event Data (ACLED), an independent research group.
Their mission, according to Abdullah, was "to retake control of areas from IS and then to defend the Syrian government military and pro-government military bases." Members of the Fatemiyoun and Zainebiyoun also participated in battles in Aleppo and southern Syria, Abdullah said.
In 2018, a Fatemiyoun official said that 2,000 of its own fighters had been killed and 8,000 wounded. No figures on Zainebiyoun casualties are available.
Smyth said the Fatemiyoun were often used as "cannon fodder."
"Let's say Lebanese Hezbollah needed to be used a little bit more readily in Lebanon, then they could pull out, leave some command elements on the ground to control Fatemiyoun, and then have the Fatemiyoun guys there," Smyth said.
Final days of Assad regime
In recent years, as the Assad regime consolidated its control over much of the country, the number of militia forces fighting in Syria dwindled. Yet even before the Assad regime's fall, there were still 2,500 to 5,000 Fatemiyoun and Zainebiyoun fighters in Syria, Smyth said.
Mostly concentrated in northeastern Syria, smaller forces operated in Damascus, and some were occasionally deployed to Aleppo and other parts of the country, he said.
As the rebels began their surprise offensive late last month, some experts predicted a fierce battle for Damascus, expecting the IRGC and its proxies to defend the regime.
Videos circulated by Iraqi militia last week showed the Fatemiyoun around the shrine of Zainab outside Damascus.
"Some of them were claiming these Fatemiyoun want to stay and defend the shrine. They're not getting ready to leave," Smyth said.
On Iranian television, IRGC officials echoed that message.
They were saying "don't worry, our boys, the guys we trained … were fighting very, very hard," Smyth said. "I haven't seen any evidence of that. There are no casualty lists. There is no claim of what was going on."
Instead, anti-government rebels found abandoned bases, capturing the scene on video.
One video shows an armed rebel fighter inside a former Fatemiyoun base shouting "Khomeini's pigs" as he rips out Fatemiyoun and Iranian flags. Another shows a larger base in Idlib with walls painted with the Fatemiyoun flag and ransacked rooms with Persian language posters and signs scattered around.
Where they went remains uncertain. Iranian officials haven't commented, but news reports have indicated that some were flown to Iran along with IRGC forces. Others are said to have crossed into neighboring Iraq or followed fleeing Hezbollah forces into Lebanon.
Smyth speculates that some remnants of the two groups might still be in Syria, awaiting evacuation. However, a return to Afghanistan and Pakistan seems improbable, given that authorities have cracked down on returning fighters.
Iftikhar Hussain of VOA Deewa contributed to this report.
