In the shadow of the Gaza conflict, armed groups aligned with Iran have stepped up a campaign aimed at pushing the U.S. to end its military deployments in Iraq and Syria. After mounting a series of direct attacks on U.S. bases in south-eastern Syria, which prompted a wave of retaliatory strikes, Iran shifted its focus to loosening the already shaky hold of the Kurdish-led Syrian Democratic Forces (SDF), which are allied with Washington, on lands east of the Euphrates River. Portraying the SDF as an occupying army aligned with a foreign power in a region predominantly inhabited by Arab tribes, Iran has been able to rally local groups to perpetrate attacks on this U.S.-backed force. While both Iran and the U.S. seem keen to avoid a wider escalation of regional conflict, the situation in eastern Syria is likely to remain volatile, at least until Israel and Hamas reach a ceasefire in Gaza. Pressing for an end to that conflict and, in the meantime, pushing the SDF to build bridges with alienated Syrian communities are ways for Washington to help defuse tensions in the region.
An Escalatory Spiral Halted
On 18 October 2023, a day after hundreds of people were killed at the al-Ahli Arab hospital in Gaza in an explosion that Arab media overwhelmingly blamed on Israel but for which Israel denied responsibility, drones and missiles were launched at U.S. military bases at al-Tanf and the Conoco gas field, both in eastern Syria. The Islamic Resistance in Iraq, an alliance of Iran-aligned formations that includes Kataib Hizbollah, Harakat al-Nujaba and Kataib Sayyid al-Shuhada, claimed responsibility for the attacks, which they labelled “revenge for Gaza”.
Part of the Hashd al-Shaabi (Popular Mobilisation), an amalgam of Iraqi militias that assembled in 2014 to fight the Islamic State, or ISIS, and were integrated into the Iraqi security apparatus in 2016, these armed groups now also operate in Syria. Working outside the Iraqi state structure with the support of Iran’s Islamic Revolutionary Guards Corps, they are stationed in government-controlled areas west of the Euphrates alongside other Iran-aligned groups. For nearly a year until the 18 October barrage these groups had not struck U.S. troops, instead observing a unilateral ceasefire they had declared in support of the newly formed Iraqi government of Prime Minister Mohammed Shiaa Sudani. The October strikes were also the first shots of some 150 they would take at U.S. assets in Syria and Iraq by the end of January 2024.
The U.S. bases’ air defence systems fended off nearly all the attacks, which caused injuries but no fatalities among U.S. forces. Retaliation was slow in coming, but in November and December the U.S. started hitting the armed groups in question in Iraqi cities and near government facilities. Strikes on Iranian-backed groups in eastern Syria and the killing of a senior Revolutionary Guards commander in Damascus in late December, both unclaimed but attributed to Israel, turned up the heat.
Worse was to come for U.S. forces in the area. A drone attack on 28 January 2024 on Tower 22, a U.S. base in Jordan near Rukban that provides support for U.S. military operations across the border in Syria, killed three U.S. soldiers and injured 40. Responsibility for the attack was claimed by the Islamic Resistance in Iraq. U.S. officials stated that the base’s air defence system mistook the incoming drone for a U.S. device returning from a mission and therefore failed to intercept it. Since it was the first attack ever by Iran-backed groups on U.S. forces in Jordan, which has long been free of the violence characterising the Syrian and Iraqi theatres of conflict, the strike in itself marked a clear provocation. Sources in the group claim that it did not anticipate killing U.S. soldiers at Tower 22, expecting that the base’s air defences would take down the drone, as had happened many times before. But by claiming U.S. lives, even if that was not the expected outcome, the attack crossed a threshold that made a forceful U.S. response all but a foregone conclusion.
The Iran-affiliated armed groups were clearly aware they had overstepped their bounds. They promptly evacuated bases in eastern Syria and western Iraq. Esmail Qaani, commander of the Revolutionary Guards’ elite Qods force, reportedly arrived in Baghdad within hours to tell the Iraqi groups to de-escalate, apparently concerned that the U.S. might retaliate against Iran directly. On 30 January, Kataib Hizbollah issued a statement announcing it would suspend attacks on U.S. troops. Other groups, such as Harakat al-Nujaba, vowed to continue their campaign but nevertheless scaled down their attacks significantly.
In an initial response on 3 February, the U.S. attacked 85 locations in Syria and Iraq. Revolutionary Guards commanders and affiliated militia members had had nearly a week to evacuate, so many of the ammunition and weapons warehouses the U.S. hit were reportedly empty, but the combined death toll still reached 51. The 34 fatalities in Syria included members of Syrian, Lebanese, Iraqi, Afghan and Pakistani groups linked to Iran. The strikes in Iraq killed sixteen Hashd members unaffiliated with the Iran-backed groups, as well as a civilian. In a second response on 7 February, a U.S. drone strike in Baghdad killed senior Kataib Hizbollah commander Abu Baqir al-Saadi. In the aftermath of these retaliatory strikes, the Iraqi armed groups continued to harass U.S. positions in Syria, albeit with lesser frequency and training their sights more on bases near the gas and oil fields in the east. On 25 February, Harakat al-Nujaba announced a temporary suspension of hostilities against U.S. forces, vowing to continue attacks on the U.S. “until the end of the Gaza war”. After a 30-day halt, Iraqi groups resumed only sporadic attacks on U.S. bases in eastern Syria.
A Shift in Focus
The Tower 22 attack marked an inflection point, with Iran and its Iraqi allies seemingly opting to dial back the intensity and scope of direct attacks on U.S. troops in its aftermath to avoid a wider escalation that could jeopardise their long-term interests. That said, the influx of weapons and fighters into eastern Syria has continued. Since the end of January, the Iran-backed groups have shifted their focus: rather than solely attacking the U.S. military, they have rallied Arab tribal militias against the SDF as a way to weaken the latter’s hold on local power while bolstering their own position in eastern Syria. This strategy has involved a growing division of labour. Those Iran-backed groups composed of fighters from outside Syria have targeted U.S. bases, while Arab tribal militias based in government-held areas and backed by the Revolutionary Guards and the Syrian government have stepped up attacks on the SDF. During February and March, these tribal militias fired rocket-propelled grenades at SDF positions along the Euphrates and attempted incursions into territory held by the group on a near-daily basis.
Targeting the SDF has a clear strategic logic: keeping the conflict local, thus posing limited risk of U.S. retaliation. (After a drone attack by Iraqi groups near the U.S. base at the Omar oil field on 5 February killed seven SDF members, the U.S. refrained from escalating.) The Arab militias oppose the Kurdish-dominated SDF’s rule over large parts of eastern Syria and have branches extending deep into SDF-controlled territory, where their kin say they are suffering under Kurdish rule. Mistrust of SDF governance is prevalent among Arab communities in these areas, which believe that the group gives Kurds preferential political and economic treatment. Arabs also resent the SDF’s compulsory recruitment practices, adding to the sources of discontent that have allowed the Syrian government and Iran to make inroads in these communities.
Iran-backed groups and the Syrian government brand the SDF an occupying army aligned with a foreign power in a bid to boost recruitment of fighters from among the tribal groups. U.S. support for Israel in the Gaza war has provided additional fodder for their enlistment campaign. Many Arabs in eastern Syria are wary of non-Arab Iran, which they suspect of having an intent to convert the locals, who are mostly Sunni Muslims, to Shiism. But for the time being, a shared sense of outrage over Gaza and Muslim solidarity has superseded these doubts.
Iran has focused its recruitment efforts on the vicinity of Khasham, a town east of Deir al-Zor, the only government-controlled area on the eastern bank of the Euphrates. By raising a loyal militia, Tehran seems to hope to secure a river crossing to facilitate lucrative smuggling and infiltration into SDF-held areas near the Conoco gas field and the U.S. base there. In November, Iran-backed groups opened recruitment offices in this area, offering monthly salaries of 1.5 million Syrian pounds ($107 at the black-market rate), twice the amount paid to Iran-backed militia fighters elsewhere in Syria, and closer to the two million pounds ($143) the SDF gives its recruits. Tribal fighters receive training at Revolutionary Guards bases in al-Bukamal and al-Mayadeen, and are equipped with light and medium weapons, including rocket-propelled grenade launchers and DShK machine guns.
Adding to the SDF’s predicament is the fact that a third regional power – Türkiye – is bent on destroying it, viewing the group as an arm of the Kurdistan Workers Party, or PKK, which Türkiye, the U.S., the EU and some other states consider a terrorist organisation. Türkiye has targeted critical infrastructure in SDF-held areas in northern and north-eastern Syria in three distinct waves of intense shelling in October, December and January in response to PKK attacks on the Turkish army in northern Iraq. Its heavy bombardment has disrupted water and electricity provision, and reduced oil and gas production, which is the main source of income for the SDF-dominated Autonomous Administration of North and East Syria. An all-out Turkish invasion aimed at defeating the SDF would likely trigger mass civilian displacement, especially of Syrian Kurds.
Iran’s Strategic Objectives
While the wave of Iran-backed militia attacks on U.S. bases since October is a response to Israel’s war in Gaza, they appear aimed at achieving three complementary strategic objectives for Tehran. First, they raise the political and strategic cost that Washington incurs by keeping U.S. troops deployed in Iraq and Syria, which it officially justifies as part of the continuing campaign against ISIS; they thereby serve Iran’s long-term goal of rolling back the U.S. presence in both countries. Iran seeks to achieve this objective by wearing down U.S. forces, with a view both to inciting U.S. politicians to call for troop withdrawal and to shaping the Iraqi domestic debate.
Admittedly, in their immediate aftermath, the attacks seem to have had the opposite effect: in mid-January, the U.S. sent 1,500 additional troops to both countries, reinforcing the 2,500 it already had in Iraq and the 900 stationed in Syria. But over time the tit-for-tat cycle in the Iraqi and Syrian theatres could erode U.S. support for future deployments, even as Iran holds the campaign at a level that does not expose it or its Iraqi allies to serious retaliation. Political debate in Washington could play a key role in this respect. Even limited additional harm to U.S. troops in Iraq and Syria could bring Congressional scrutiny of the domestic legal authority and rationale for their continued deployment, a scenario that the White House clearly wants to avoid, particularly in an election year. During his term in office, Donald Trump, the Republican challenger to President Joe Biden, ordered and then partly walked back a U.S. withdrawal from Syria. He may well seek to exploit casualties in Syria to lambast the Biden administration’s Middle East policies, despite the likelihood that he would face resistance to this position from within his own party.
Tehran’s primary means of compelling a U.S. withdrawal, however, is through shaping the political debate in Iraq. The U.S. counterstrikes on Iran-aligned Hashd groups have embarrassed the Sudani government, under whose command they nominally fall since they form part of the Iraqi security structure. They threaten to disrupt the delicate balancing act of a prime minister who has tried to placate the armed groups pushing for an expedited U.S. departure at the same time as working to mollify other constituencies, like the Kurds, Sunni Arabs and some Shiites, who fear an even greater Iranian presence in the event that the U.S. leaves abruptly.
Pressured by Iran-aligned parties, on whose support it depends, the Sudani government has moved forward with attempts to terminate the mandate of the U.S.-led anti-ISIS coalition in Iraq. These efforts intensified after U.S. retaliatory attacks extended beyond strikes on pro-Iranian armed groups to targets closer to the government. U.S. drones hit Hilla city on 26 December and Baghdad on 4 January, causing casualties not only among these groups, but also in the Hashd and federal police forces. The government, which until then had defended the partnership with the U.S., condemned it for violating Iraqi sovereignty and launched talks with the Biden administration to phase out the international coalition. If its slow-moving efforts, which neither side appears keen to accelerate, succeed, they could also undermine the international legal basis for the presence of U.S. troops in Syria, since the principal U.S. justification for military operations there is the defence of Iraq from ISIS.
Iran’s second strategic objective is to expand its own footprint in eastern Syria, which it uses as a gateway to the Levant, funnelling arms to Hizbollah in Lebanon as a means of deterring Israel. Its main goal in this regard would be U.S. withdrawal from al-Tanf, which sits on a major highway between Iraq and Syria and represents a significant obstacle to Iranian power projection. While the al-Tanf base does not block Iranian movement of troops and materiel across Syria as such, the base and its surrounding 55km “deconfliction zone” prohibits the entry of U.S. opponents and counters Iran’s ability to establish a permanent presence that connects its strategic hubs in eastern Syria with those in the south of the country.
Iran’s third strategic objective is to rehabilitate the Syrian government. To this end, it seeks to destabilise SDF rule in northern and eastern Syria. Co-opting Arab tribes, particularly in areas with major oil and gas deposits, may allow Iran to build up a support base that could enable Syrian government forces, in the event of a U.S. withdrawal, to retake the most valuable part of eastern Syria without a fight.
At the same time, the latest round of violence in eastern Syria has exposed the limits to what Iran can do there. It has highlighted the absence of a capable local proxy force comparable to its allies in Iraq, Lebanon and Yemen. To compensate for this limitation, it has relied on a division of labour between foreign and local groups to do its bidding, but this approach has seen only partial success. Tehran has been able to stir up Syrian Arab militias against the SDF, and these groups have served to undermine the already tenuous control and legitimacy of the Kurdish-led administration in a resource-rich and predominantly Arab tribal region, while wearing down the SDF’s forces with skirmishes across the Euphrates. But these militias still lack infrastructure, organisation and materiel, and the lack of ideological alignment between the militias and Iran also makes them unlikely candidates for a full-blown partnership like that of Iranian clients elsewhere.
To put pressure on the U.S., Iran still relies heavily on groups from outside Syria, particularly those belonging to the Islamic Resistance in Iraq. But this gambit is risky. Any serious escalation in eastern Syria involving these Iraqi groups risks U.S. retaliation on Iraqi soil, whereas relying on a Syrian proxy force to conduct attacks on U.S. bases would contain the conflict within Syria’s borders. Worsening conflict could have serious knock-on effects on Iran’s partners and interests in Iraq, as well as jeopardise that country’s hard-won but fragile stability – a scenario that interestingly is as unpalatable for Tehran as it is for Washington.
Prospects for Eastern Syria
For the U.S., Iran’s pursuit of its strategic objectives could compromise its position in eastern Syria. Retaliation for the Tower 22 attack appears to have been partially successful in deterring attacks, as shown by the Iran-aligned armed groups’ decision to tone down attacks. The new status quo nevertheless remains precarious. The relative calm in the attack’s aftermath yielded to alarm at the threat of a wider regional conflagration following Israel’s 1 April strike on the Iranian consulate in Damascus, which prompted Iran’s first-ever direct attack on Israel on 13-14 April. Washington moved to de-escalate, helping reduce tensions once more. But events in Gaza, or intensified Israeli attacks on Iranian assets in Syria, could trigger a new round of escalation in eastern Syria. Iran-aligned groups are primed to continue harassing U.S. troops in Syria in either eventuality, although possibly in ways that do not expose these groups and Iranian interests to violent retribution.
Likewise, the tribal groups’ campaign against the SDF, which in contrast to attacks on U.S. troops carries little risk of retaliation for Iran, will almost certainly continue and may even accelerate. A progressively weaker SDF will leave U.S. bases in the most resource-rich areas of eastern Syria – the oil and gas fields east of al-Mayadeen and Deir al-Zor – in an increasingly hostile environment in which they would find their presence difficult to sustain.
There are things that could help lower the temperature in the area. Reaching a durable ceasefire in Gaza would almost certainly help slow the anti-U.S. momentum across the region that Iran and its allies are exploiting, as evidenced by Iran-backed groups’ cessation of hostilities during the temporary halt in hostilities in November. A truce would also improve the climate for negotiations over the U.S. presence in Iraq. But Washington would also be well advised to pay attention to the condition of the SDF, particularly in the triangle south of the M7 highway, which connects Deir al-Zor to Syria’s northeast, with its significant hydrocarbon deposits. The U.S. should apply pressure on its partner to address the grievances of the local Arab population that have made some of its members vulnerable to co-optation by Iran. It may need to mediate between the Arabs and the SDF, as it did in September 2023, when it brokered an end to intense clashes triggered by the SDF’s arrest of a tribal leader. Both the U.S. and the SDF should also give serious consideration to the area’s future, and do some contingency planning. Despite the Biden administration’s clear intent to maintain the U.S. military presence in Syria, U.S. politics remain unpredictable. A precipitous U.S. withdrawal would leave the SDF dangerously exposed to assault by Türkiye and/or the Syrian government, potentially initiating a new round of violence in Syria’s volatile east.
Source » crisisgroup