Deir ez-Zor campaign (2017–2019)

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Deir ez-Zor campaign (2017–2019): a concise, easy-to-understand version

Overview
The Deir ez-Zor campaign was a major battle in eastern Syria during the fight against the Islamic State (ISIL). Led by the Syrian Democratic Forces (SDF) with strong American-led coalition support, the operation aimed to expel ISIL from the Deir ez-Zor Governorate, especially the area east of the Euphrates River and along the Iraqi border. The campaign stretched from September 2017 to March 2019 and ended with ISIL’s territorial defeat in the region.

Who fought
- Ground forces: Syrian Democratic Forces (SDF), including the Deir ez-Zor Military Council and allied Kurdish and Arab units; various local and regional factions.
- International partners: United States and other coalition members provided air power, logistics, and advisory support.
- Adversaries: Islamic State (ISIL) fighters defending towns, oil fields, and pockets along the Euphrates.
- Other fronts: The campaign ran alongside parallel operations by the Syrian government and other forces in the broader region.

Phases of the campaign
- Phase 1: 8 September 2017 – 5 March 2018
- The SDF began the ground push north and east of Deir ez-Zor city, rapidly capturing villages and key locations, including parts of the northern Deir ez-Zor countryside and the Industrial City area.
- ISIL offered stiff resistance with counterattacks, including VBIEDs (vehicle-borne explosives), as the SDF pressed toward the Euphrates’ eastern bank.
- Phase 2: 1 May – 4 August 2018
- The campaign continued toward the Iraqi border and the Middle Euphrates Valley, with several fronts opening and more territory changing hands.
- In spring 2018, the operation paused briefly due to Turkey’s assault on Afrin, while ISIL remained under pressure on other fronts.
- Phase 3: 10 September 2018 – 23 March 2019
- The third and final phase, named during the campaign as the push toward the pocket that ISIL held around Hajin, al-Susah, Baghuz Fawqani, and surrounding areas.
- The SDF launched multi-front assaults, supported by heavy coalition airpower, to seal ISIL in the Middle Euphrates River pocket and clear the last remaining towns.

Key milestones and turning points
- Late 2017: The SDF extended its control along the eastern bank of the Euphrates as ISIL fought to defend oil fields and towns near Hajin and Abu Kamal.
- December 2017: ISIL’s last major stronghold areas near Hajin became the focus as SDF advances pushed toward the Iraqi border.
- December 2017 – February 2018: The SDF captured a string of towns and oil fields, steadily tightening the noose around ISIL’s eastern Deir ez-Zor pocket.
- March 2018: The campaign paused temporarily due to Turkey’s Afrin operation, with forces redeployed to other fronts.
- May 2018 – August 2018: The operation resumed as Operation Roundup, with continued advances toward the Iraqi border and further ISIL territory gains.
- September 2018 – January 2019: The third phase intensified, moving toward Hajin and the surrounding area. Hajin became ISIL’s main remaining urban stronghold in the pocket.
- 14 December 2018: Hajin, ISIL’s last major urban center in the pocket, was captured by the SDF.
- January–February 2019: Fighting continued around the remaining ISIL pockets near Al-Susah, Al-Marashidah, Al-Shajlah, and Baghouz, with heavy airstrikes and persistent siege conditions.
- 13 February 2019: ISIL’s last major fortified position, Baghouz Fawqani, fell to the SDF.
- 23 March 2019: The SDF announced the full liberation of ISIL’s enclave in the Deir ez-Zor region, marking the end of ISIL’s territorial control east of the Euphrates.

Territory and impact
- The campaign resulted in the SDF and allied forces capturing about 14,020 square kilometers of territory, including areas east of the Euphrates and along the Iraqi border.
- The fighting displaced tens of thousands of civilians and caused thousands of deaths on all sides, with many civilians killed in airstrikes and heavy fighting.
- The operation drastically degraded ISIL’s ability to hold territory in eastern Syria and reduced its power projection in the region.

Aftermath and significance
- ISIL’s territorial caliphate was dismantled in the Deir ez-Zor pocket, though the group remained capable of insurgent attacks and guerilla-style warfare.
- The campaign highlighted the cooperation between the SDF and the U.S.-led coalition in ground offensives supported by air power, intelligence, and logistics.
- As ISIL lost physical territory, the SDF and coalition shifted focus to counterinsurgency, intelligence, and humanitarian challenges, including the handling of foreign fighters and civilian evacuations.
- Debates about tactics emerged, including criticisms of heavy air power and its impact on civilians and infrastructure. Some commanders and observers argued for different approaches, particularly in terms of ground force deployment and civilian safety.

Outcome
The Deir ez-Zor campaign succeeded in defeating ISIL’s presence in the eastern Deir ez-Zor region and near the Iraqi border. By March 2019, ISIL had been driven from its last pockets in this area, and the SDF, with coalition support, declared victory. The campaign ended ISIL’s substantial territorial control east of the Euphrates River, though ISIL later continued insurgent activities and attacks from hidden networks.