Deir ez-Zor offensive (September 2017–present)

The Deir ez-Zor offensive, named by the SDF as the al-Jazeera Storm campaign, was a military operation launched by the Syrian Democratic Forces (SDF) against the Islamic State of Iraq and the Levant in the Deir ez-Zor Governorate with the goal of capturing swathes of territory east of the Euphrates in the eastern countryside of the Deir ez-Zor Governorate.

The offensive is concurrent with another SDF offensive, the Raqqa campaign conducted against ISIL's capital city and stronghold in Syria, as well as with the Central Syria campaign and 2017 Euphrates Crossing offensive, in which the Syrian Army is also trying to capture territory from the Islamic State of Iraq and the Levant.

Background
On 25 August 2017, around 800 fighters from the Syrian Elite Forces defected to the SDF's Deir ez-Zor Military Council. On the same day, Ahmad Abu Khawla, commander of the Deir ez-Zor Military Council, announced that it would launch an offensive north of Deir ez-Zor within several weeks. Just before the start of the offensive, the SDF received a large amount of new weaponry and ammunition from CJTF–OIR.

The offensive


On 8 September, the SDF launched the offensive by attacking of ISIL-held villages in the northern Deir ez-Zor countryside; on the next day, the offensive was officially announced in the al-Shaddadah Subdistrict with the stated aim of expelling ISIL from all areas north and east of the Euphrates. In course of the next two days, the SDF rapidly advanced and captured numerous villages. According to pro-Syrian opposition media, this quick initial progress was due to ISIL forces retreating from areas that were difficult to defend in the face of heavy CJTF–OIR airstrikes.

On 10 September, the SDF fought its way into the fortified Industrial City, directly north of Deir ez-Zor city, while capturing more nearby villages. On 12 and 13 September, the SDF captured several locations at Deir ez-Zor's northern entrance (including the former Brigade 113 and al-Niran Battalion bases, the Sadkob station and part of the sheep market) as well as the silos and cotton storages in the Industrial City. The coalition also made further progress in the desert north of Deir ez-Zor, where it advanced 60km. Despite these successes for the SDF, ISIL had significantly increased their resistance and began to launch repeated counter-attacks supported by VBIEDs in an attempt to stall the offensive and/or recapture territory.

Meanwhile, the SDF leadership stated that their forces would not attack the troops of the Syrian government which were battling ISIL on the west side of the Euphrates. On 15 September, Ahmad Abu Khawla, commander of the SDF's Deir ez-Zor Military Council, however stated that it will not allow government forces to cross the Euphrates. The next day, alleged Syrian or Russian aircraft bombed SDF positions on the eastern bank of the Euphrates, injuring 6 SDF fighters. In response, CJTF–OIR stated that while they were putting their "full efforts into preventing unnecessary escalation among forces that share ISIS as our common enemy", "Coalition forces and partners always retain the right of self-defense". In this context, Institute for the Study of War expert Chris Kozak said that neither Russia nor the United States had an interest in escalating a conflict between them. "The real threat [is instead] that the partner forces on the ground—the SAA and the SDF—come close [to confrontation] before the US and Russia can slow them down." The government and the SDF are rivals in Deir ez-Zor Governorate, as both sides want to capture the region's natural resources (most importantly its oil fields).

On 17 September, SDF captured a textile factory and a roundabout 7 km from Deir ez-Zor city. On 20 September, the SDF opened a second front against ISIL east of Deir ez-Zor near the border with Iraq, and six villages alongside the M7 highway in quick order, thus advancing towards the oil-rich eastern countryside of Deir ez-Zor. As a response to the SDF advances, ISIL began to launch raids into SDF-held areas in southern al-Hasakah Governorate, reportedly ambushing and killing several SDF fighters on 21 and 24 September. On 21 September, Russia warned it would attack SDF fighters if provoked.



ISIL counter-attacks did little to impede the SDF offensive, however, and the SDF proceeded to capture the Al-Izba and Conoco gas fields, the Derro oil fields, and the Al-Bazikh mountain chain. On 25 September, however, Russian aircraft, as well as Syrian and Russian artillery bombarded the SDF troops at the Conoco gas field, causing several casualties. The SDF responded to this by stating that "Russian and regime forces have mounted a treacherous attack against our forces... with artillery and aircraft" and that they would "use our legitimate right to self-defense". Further Russian bombing was reported on 27 September, with SOHR claiming 6 civilian casualties in Marat, to the east of the Euphrates River opposite Deir Ezzor Military Airbase. Iranian missile strikes on ISIL in the southern and eastern parts of the province were also reported on 24 September.

Despite the airstrike incident, the SDF continued the offensive and pushed ISIL out of numerous villages over the following days. At al-Suwar, however, the SDF troops met fierce resistance on 24 September and a heavy battle ensued;   after six days of fighting the town finally fell. The SDF then attempted to further advance in al-Suwar's surroundings, while ISIL launched counter-attacks to retake it. On 30 September, the SDF took control of the Jafra oil fields, one of the "most important sources of income for IS". Between 1 and 9 October, the SDF captured several more villages and repelled further ISIL counter-attacks,     with ISIL resistance in these areas being mostly light. This was due to ISIL relocating many of its troops from its frontlines with the SDF to face the Syrian Army.