Four experts discuss what Washington can do about the latest spike in militia attacks against U.S. bases and local partners—even as they try to sustain the counterterrorism mission against the Islamic State.
On November 15, The Washington Institute held a virtual Policy Forum with Michael Knights, Wladimir van Wilgenburg, Devorah Margolin, and Andrew J. Tabler. Knights is the Institute’s Bernstein Fellow and cofounder of its Militia Spotlight platform. Van Wilgenburg is coauthor of the book The Kurds of Northern Syria: Governance, Diversity, and Conflicts. Margolin is the Institute’s Blumenstein-Rosenbloom Fellow, focusing on terrorism governance and the role of women in violent extremism. Tabler is the Institute’s Martin J. Gross Senior Fellow and former director for Syria at the National Security Council. The following is a rapporteur’s summary of their remarks.
The so-called “Islamic Resistance in Iraq” is responsible for much of the kinetic activity against U.S. forces in Iraq and Syria over the past month. This umbrella brand includes all the usual Iran-backed militia suspects in Iraq. Indeed, The Washington Institute’s Militia Spotlight team has kept a running tally of their attacks by tracking social media and other outlets where such claims are made.
The groups carrying out these strikes have divided them into two main areas of responsibility. One portion focuses on U.S. bases south of the Euphrates River, in western Iraq (e.g., al-Asad Air Base) and southern Syria (al-Tanf garrison). The other focuses on U.S. targets north of the Euphrates, in northern Iraq (e.g., Harir Air Base) and eastern Syria (al-Shadadi, Rmelan), launching their attacks from areas in Sinjar, Mosul, the Nineveh Plains, and Kirkuk. In addition, a mix of Iran-backed groups on the west bank of Syria’s Middle Euphrates River Valley have been firing short-range rockets at U.S. bases and adjacent elements of the Syrian Democratic Forces (SDF) around oil fields in Deir al-Zour province. Some longer-range drone attacks on Shadadi, Rmelan, and Tal Baidar are also launched from this valley.
On the Israel-Lebanon border, the rules of the game—acceptable targets, red lines, et cetera—are well understood. The same is true between the United States and Iran in Syria and Iraq. There is a level of militia harassment that Washington considers acceptable, but other Iran-backed kinetic actions will elicit a stronger U.S. response. The specific trigger often depends on the sophistication of a given attack and whether or not it results in casualties. This March, for example, U.S. forces conducted an airstrike immediately following a militia attack, partly because an American contractor was killed and also because the attack displayed a qualitative rise in capability.
Today, Iran-backed militias are continuing to test Washington’s restraint by increasing their attacks, mostly in Syria. In response, U.S. forces have undertaken three airstrikes and an indeterminate number of counter-battery artillery strikes (in general, U.S. officials publicly disclose only the airstrikes). Although the latest base attacks are intended to be nonlethal, they still run the risk of accidentally killing Americans and greatly escalating the situation. Under those circumstances, the United States might strike much harder in Syria—or even against militia leaders in Iraq, broader Iranian targets in the region, or economic interests in mainland Iran.
Wladimir van Wilgenburg
The current situation in northeast Syria poses multiple challenges for the Syrian Democratic Forces (SDF). As the main territorial battle against the Islamic State (IS) wound down in past years, the Kurdish-led SDF were not initially interested in occupying areas around Raqqa and Deir al-Zour city. Yet the United States encouraged them to enter those cities, even though Raqqa has only a small Kurdish population and Deir al-Zour has none at all.
This situation spurred the SDF to work with Ahmad Hamid al-Khubayl (better known as Abu Khawla), an unpopular figure but someone whom the Kurds believed could help them control Deir al-Zour. Over time, however, local anger toward the SDF intensified due to Abu Khawla’s abuses of power and failure to provide basic services such as access to clean water.
In August, these grievances led to an Arab tribal insurgency against the SDF. Although limited at first, the insurgency spread as casualties mounted, eventually reaching Diban, a town under the control of tribal leader Ibrahim al-Hifl. In the end, the insurgency failed because the majority of local Arabs did not join; after Diban was recaptured, other areas surrendered without a fight.
The Assad regime tried to exploit the insurgency and has continued sowing dissent among the Deir al-Zour population. After the initial fighting wound down, several signs of regime support became evident: Abu Khawla asked Damascus for help in removing the SDF from Deir al-Zour; Ibrahim al-Hifl called for more attacks on the SDF from regime territory; the SDF captured multiple members of the pro-regime National Defense Forces while they were operating in the area; and new attacks against SDF units emerged in October.
Iran and the Assad regime want the United States to leave Syria, and they are using Arab tribal unrest against the SDF as an opportunity to achieve that goal. Without U.S. support, the SDF could not have quelled the tribal insurgency. Hence, while the U.S. presence in Syria remains centered on combating IS, Washington must formulate a strategy that extends beyond that counterterrorism mission—one with more focus on strengthening the SDF’s position. Many locals still prefer the SDF over the Assad regime, but their numerous grievances remain ripe for exploitation by Tehran and Damascus.
The Islamic State has managed to maintain some degree of “shadow governance” in parts of northeast Syria—it still collects taxes, issues administrative documents, and maintains moral policing units. More important, it never gave up its ambition to regain territorial control. These IS governance activities indicate that the group may be stronger than many observers assume.
Regarding terrorist activity, IS has claimed fewer attacks so far this year. Through August, U.S. Central Command reported eighty-seven anti-IS operations conducted in partnership with the SDF and three unilateral U.S. operations. Additionally, the coalition arrested senior IS leader Muhammad Sakhr al-Bakr earlier this month in Raqqa. Repatriation of IS detainees and family members has increased in 2023, with 3,200 Iraqis sent home (mainly women and children) along with 590 other foreign nationals.
Following the October 7 Hamas attack on Israel, IS refrained from any explicit references to the incident. There is no love lost between the two terrorist organizations—IS leaders still view Hamas as an apostate group because of its Palestinian national aspirations. Yet IS has called for more attacks against Jews since October 7, specifically mentioning targets in North America and Europe.
In the coming months and years, the United States and its partners will have a lot of “known unknowns” to keep an eye on in northeast Syria. For one, it is unclear how the Hamas-Israel war will affect the coalition presence and counter-IS mission in the long term. Sabotage and general unrest in SDF-controlled territory are already distracting partner forces from that mission. Climate change may also have growing effects on the ground, as various factions fight over resources. The looming U.S. presidential election makes the future of the American presence uncertain as well.
Andrew J. Tabler
U.S. forces in Iraq and Syria have faced more than fifty attacks in the current wave of violence, resulting in injuries to fifty-nine American personnel. Fortunately, all of these personnel have returned to service, but as attacks continue, the possibility of Americans getting killed becomes increasingly likely. That scenario would no doubt generate more calls back home to withdraw U.S. forces, which is exactly what Iran, the Assad regime, and Russia want. In Syria, these actors are especially keen on stirring the pot in areas controlled by the SDF. The U.S. presence gives the SDF strength to act in Deir al-Zour, but the Kurdish-led force would have difficulty operating there alone given its local demographic disadvantage.
Regarding the Gaza situation, some believe that the Hamas assault was part of an Iranian plan to encircle Israel and suck the United States into a regional crisis. This is not necessarily the case. Yet Iran does view the U.S.-Israel alliance as being so close that attacking one country is virtually the same as attacking the other. It also understands how sensitive the United States is to American casualties—a sensitivity that will only increase amid the upcoming U.S. election year. Accordingly, Tehran may soon step up its efforts to push U.S. forces out of the region.
In this regard, attacking U.S. targets in Syria presents lower risks and greater rewards than attacking in Iraq or elsewhere. Syria has greater freedom of maneuver and more malleable rules of the game. Yet this same lack of firm rules could lead to unintended escalation between the multiple foreign militaries and proxies still operating in Syria.
This summary was prepared by Kyle Robertson. The Policy Forum series is made possible through the generosity of the Florence and Robert Kaufman Family.
Michael Knights is the Jill and Jay Bernstein Fellow at The Washington Institute and cofounder of the Militia Spotlight platform, which offers in-depth analysis of developments related to Iran-backed militias.
Andrew J. Tabler is the Martin J. Gross Senior Fellow in the Linda and Tony Rubin Program on Arab Politics at The Washington Institute, where he focuses on Syria and U.S. policy in the Levant, and Director of the Institute's Junior Research Program.