Countering Iran in East Syria Means Moderating the SDF

On August 6, armed groups crossed the Euphrates River and attacked several villages controlled by the U.S.-supported, Kurdish-dominated Syrian Democratic Forces (SDF). Located near U.S. military positions at the Conoco and al-Omar oil facilities in the eastern province of Deir al-Zour, the villages were swarmed by fighters aligned with Bashar al-Assad’s regime and Iran.

Over the past year, Washington has blunted Tehran’s efforts to push U.S. forces out of Syria and Iraq, in part by helping the SDF repel attacks similar to last week’s. Yet despite suppressing various militia provocations and local uprisings, the SDF now faces growing pressure in Arab areas under its control—particularly from the so-called “Tribal Forces for the Liberation of al-Jazira and the Euphrates,” a rebranded Iran-backed proxy that seems bent on making the challenge far more difficult in the months ahead. At the same time, Iranian militia attacks on U.S. forces have spiked since July, feeding concerns that Washington will withdraw its troops. Rather than simply assuaging these concerns, however, Washington may find that they provide leverage—on partners and adversaries alike—to change the worsening dynamics in eastern Syria, regardless of whether a withdrawal happens in the coming year or not.

The Attacks, the Response, and the U.S. Presence

The groups that launched last week’s attack included the National Defense Forces, a paramilitary supported by the Assad regime and Iran’s Islamic Revolutionary Guard Corps (IRGC); the Arab Tribal and Clan Forces, led by Ibrahim al-Hifl, a pro-regime sheikh from the Ougaidat tribe; and the aforementioned “Liberation of al-Jazira” group led by Hashim al-Sattam (aka Abu Bassam), another Ougaidat leader who has sided with Assad and Iran. In each case, fighters used mortars and artillery to briefly take the villages of Diban, al-Latwa, and Abu Hamam, leaving six SDF soldiers dead and nine injured. The SDF quickly retook the villages with U.S. assistance, including attack helicopters.    

Hifl—who led an uprising against the SDF in August 2023—declared that the assault was the beginning of a war to “cleanse” the area of “terrorist Qandil gangs,” referring to the Kurdistan Workers Party (PKK) leadership that largely controls the SDF from bases in Iraq’s Qandil Mountains. His remarks were particularly significant given recent clashes in northern Syria between the SDF and militias supported by Turkey, which has fought the terrorist-designated PKK at home and abroad for decades. These northern clashes followed reports of talks between Syrian and Turkish officials with the apparent aim of arranging a meeting between Assad and Turkish president Recep Tayyip Erdogan, in line with the growing regional normalization of relations with Damascus.

Meanwhile, next month marks the ten-year anniversary of the U.S.-led war against the Islamic State (IS), which saw American forces deployed to Syria in 2015 to support the SDF. Since the territorial defeat of IS in 2019, and in lieu of a viable settlement to the Syria war, around 900 U.S. personnel have remained in the east to help prevent IS from reconstituting. This U.S.-monitored zone—dubbed the Eastern Syria Security Area (ESSA)—is home to a number of Sunni Arab tribes that have longstanding grievances against the SDF, ranging from sectarian issues with the group’s Kurdish leadership to criticisms that SDF officials favor certain Arab tribes and clans to the detriment of others.

Some of these tribal factions have steadily escalated their grievances into armed action against the SDF—particularly elements of the Ougaidat tribe. Notably, many Ougaidat also hold longstanding grievances against the United States, dating back to the 2003 invasion of Iraq. (The tribe is prevalent in both countries and harbored numerous Baath officers after Saddam Hussein’s fall.)

When the SDF arrested Abu Khawla al-Dayri—the head of the “Deir al-Zour Military Council”—on corruption charges in August 2023, it set off a tribal uprising that took ten days to suppress. Locals briefly rebelled again in late September, beginning with a river assault by Hifl’s Arab Tribal and Clan Forces against SDF positions on the eastern bank of the Euphrates. Hifl originally hails from Diban but now operates from Assad-controlled areas directly across the river, including the Iranian stronghold of Mayadin. Throughout autumn 2023 and spring 2024, he continued to launch attacks from these areas, causing the SDF to return fire.

Besides cracking down on local officials, the SDF also reportedly took over school buildings throughout Deir al-Zour province, disrupting local education and driving up tensions with Arab residents. The group apparently took this step following reports that Iran and Russia were trying to exacerbate SDF-tribal friction in order to pressure the United States to leave Syria. These tensions have only worsened amid the Hamas-Israel war in Gaza, during which Iranian militias have attacked U.S. targets in Syria over 100 times, spurring periodic U.S. counterstrikes.

How Iran Exacerbates Arab Tribal Tensions

According to local sources, Hifl’s position has eroded over the past three months due to his openly pro-regime position and cross-river attacks against the SDF. In late 2023 and early 2024, the Assad regime supported him by providing assistance and giving him freedom of movement throughout the western part of Deir al-Zour province, which straddles both sides of the Euphrates. But this came at a cost. Many of Hifl’s followers seemed uncomfortable with his pro-Assad stance, especially those from the SDF-controlled Jazira region east of the Euphrates, leading many to desert or return home under SDF amnesties.

When Hifl’s attacks intensified earlier this year, the SDF answered by stepping up its shelling along the river’s western bank—not just against Hifl’s position, but also against populated areas. In response, angry local residents demanded that the Assad regime stop Hifl’s attacks. Soon thereafter, Syrian intelligence chief Husam Luqa issued an order—reportedly at Russia’s urging—to stop all anti-SDF attacks and avoid further escalation, leading to a period of calm in May-June.

Yet other disruptive Iran-backed forces soon came to the fore. The most prominent was Hashim al-Sattam’s “Lions of the Ougaidat Brigade”—later renamed the “Tribal Forces for the Liberation of al-Jazira and the Euphrates”—which began recruiting fighters for renewed attacks against the SDF. His connections to Iran are extensive; he serves as an official in the IRGC’s office in Mayadin and recruits locals in Diban (his hometown, much like Hifl). With funding from the IRGC and its smuggling and narcotics networks, Sattam’s group was able to lure members away from Hifl’s militia and is now estimated to number as many as 800 fighters in four units.

Leading up to last week’s attacks, Sattam reportedly organized the river assault and contacted his relatives in Diban to launch an uprising against the SDF when his forces entered the village. Although Hifl’s forces may have captured all the headlines following the attacks, Sattam and his Iran-backed group appear to have played a much larger role in actually conducting the operation.

Policy Recommendations

In light of these events, Iran’s efforts to exacerbate tensions in eastern Syria appear to be expanding in lockstep with its efforts to expel U.S. forces. As Washington contemplates a potential withdrawal down the road, it should take measures now to avoid a scenario in which the SDF suffers an Afghanistan-like collapse while pro-Assad and pro-Iran forces triumphantly return to the east. This includes sustaining both diplomatic support for the anti-IS mission in Syria and military support for the SDF in repelling attacks from Assad/Iran-controlled areas across the Euphrates.

U.S. officials must also acknowledge that local friction has spiked in part because the SDF often takes a heavy hand when suppressing tribal uprisings or otherwise dealing with local Arab communities. Tensions related to the Gaza war have only exacerbated these problems. Although Washington cannot do much about the latter factor at the moment, it can change how it deals with the SDF.

To be sure, after a decade of fighting IS “by, with, and through” the SDF, the United States still relies heavily on the group’s administration of eastern Syria. Yet the SDF’s Kurdish-dominated leadership has alienated Arab tribes, and Washington’s past entreaties have failed to liberalize the group’s approach. The current dynamic is unsustainable—to change it, Washington could leverage the specter of a U.S. withdrawal to compel the SDF to be more accommodating toward Arab tribal communities. U.S. officials should also urge the group to identify and engage with more moderate tribal leaders (i.e., those more favorable toward the United States and not prone to the Salafist strains of thought at the core of IS ideology). These leaders could in turn serve as the backbone of new Sunni local forces allied with the SDF. This would likely take some time (and arm twisting), but the potential long-term benefits are considerable.

Such efforts would be even more effective if combined with U.S. and European support for projects related to drinking water, irrigation, and farming. These initiatives could help young Syrians build better livelihoods than what they are currently being offered by Iran and the Assad regime.

One practical place to start is by encouraging the SDF to withdraw from schools in Deir al-Zour, which may help decrease tensions and make local residents less likely to fall under the sway of Iran-backed figures like Sattam. Allowing instruction to resume would have the added benefit of producing better-educated youths who may be less likely to join IS or other extremist groups in the future.

Whatever approach Washington takes toward the latest clashes, it should realize that withdrawing from Syria now—with IS resurgent, the threat of broader regional war increasing, and Iran’s so-called “axis of resistance” emboldened—would be a mistake. To sustain America’s presence and the viability of its local partner forces, U.S. officials need to moderate the SDF’s problematic approach to governance.

Andrew Tabler is the Martin J. Gross Senior Fellow at The Washington Institute and former director for Syria on the National Security Council.