Syrian Desert campaign (December 2017–present)

The Syrian Desert campaign (December 2017–present) is a campaign being waged by Syrian government forces and their allies from Iran and Russia against the remaining forces of the Islamic State of Iraq and the Levant (ISIL) in Syria.

Background
Following a series of campaigns between 2016 and 2017 targeting ISIL's territory, by the American-led CJTF-OIR coalition and SDF, the Syrian government and allied forces, and Turkey, along with the Turkish-backed Free Syrian Army, the remnants of ISIL's forces west of the Euphrates River withdrew into a large pocket in the Syrian Desert, stretching between the western Homs Governorate and the eastern Deir ez-Zor Governorate, from where they utilized guerrilla tactics to target pro-government forces.

2017
The Syrian Army's 5th Legion, supported by the Iranian IRGC and Lebanese Hezbollah, reportedly seized 50 square kilometers of desert territory in the southeastern countryside of Deir ez-Zor, expanding their buffer-zone around the strategic T-2 Pumping Station.

2018
In mid-January 2018, five Hezbollah fighters were killed by ISIL in the eastern countryside of Homs, including a prominent commander.

On 17 March, 14 soldiers were killed when ISIL forces captured the T-2 Pumping Station. In the following days, government forces made attempts to recapture T-2. One week after the capture of the station, 26 government and 9 ISIL fighters were killed during clashes in the desert near Mayadin. Between 24 and 29 March, several ISIL attacks were repelled in the Mayadin area, while between 31 March and 1 April, ISIL forces were driven back from the T-2 area.

In early April, ISIL forces in the Homs Governorate employed an Inghimasi attack on the Shaer gas field near Palmyra. The battle lasted for several hours, with the attack eventually being repelled by the Syrian Army with assistance of Russian attack helicopters. Concurrently, ISIL seized several points between Abu Kamal and Mayadin. Attacks were also conducted along the Sukhnah-Deir ez-Zor highway. Mid-April, ISIL attacks south of Qaryatain in Homs province left 18 pro-government and 5 ISIL fighters dead, with the militants seizing several positions. ISIL attacked to make further advances by seizing an air defense base south of the town, but were repelled by the Syrian military which was supported by Russian attack helicopters. Russian-backed government forces also regained positions along the Sukhnah-Deir ez-Zor highway. Meanwhile, ISIL attacks continued in the Mayadin area and on 18 April, 25 pro-government and 13 ISIL fighters were killed in clashes, while on 20 April, ISIL attempted to attack the T-3 Pumping Station.

Between 8 and 11 May, the Syrian Army managed to push ISIL 60 kilometers from Mayadin, clearing 1,500 square kilometers of territory in an attempt to split the ISIL pocket in the desert. On 22 May, an ISIL attack involving suicide bombers and armored vehicles on a military outpost near the T-3 Pumping Station left between 26 and 30 pro-government fighters dead, according to the pro-opposition Syrian Observatory for Human Rights (SOHR) and local residents, while the military put the death toll at 16. The next day, ISIL militants attacked a Syrian-Russian military convoy near Mayadin, leaving 35 pro-government forces dead, including nine Russians. Four of the Russians were regular soldiers, while Russia reported that 43 attackers were also killed during the fighting. Three days later, ISIL conducted more attacks near Mayadin and Abu Kamal.

On 4 June, ISIL attacked government forces along a 100-kilometer front from Mayadin to Abu Kamal, capturing two or three towns on the western bank of the Euphrates. The militants attacked on two fronts, with ISIL fighters coming from both the desert, west of the Euphrates, and from their territory on the eastern bank of the river. A few days before the assault, around 400 ISIL fighters crossed the Euphrates from their enclave to the east following heavy shelling of government positions. The capture of the towns cut the Deir ez-Zor-Abu Kamal highway. The following day, pro-government forces recaptured the areas they had lost.

On 8 June, ISIL renewed its offensive and managed to break the Army's lines around Abu Kamal by using 10 suicide bombers, including several SVBIEDs. ISIL fighters managed to break into the city and fighting came close to the city center. The attack once again cut the highway. However, soon the Army launched a counter-attack and by the following day it was reported that the military managed to re-secure the city. During the fighting, the commander of the Syrian Army's 11th Tank Division, General Ali Muhammad al-Hussein, was killed in clashes on the outskirts of Abu Kamal. The commander of Hezbollah's Rocket Division and two Iranian IRGC members, including an officer, were also killed. On 10 June, ISIL's offensive against Abu Kamal was still continuing, before the militants withdrew from the city on 11 June. Overall, 246 pro-government and 138 ISIL fighters were killed between 22 May and 11 June.

On 17 June, ISIL launched a surprise attack on government forces around the T-3 Pumping Station, destroying one tank and killing several government soldiers. The next day, government reinforcements from the Republican Guard, National Defense Forces, and Liwa Fatemiyoun as well as additional Hezbollah fighters, were sent in preparation for a new military operation against ISIL in the region. The same day, the military seized several ISIL positions between T-2 airbase and al-Hamima and by 20 June, the Syrian Army, supported by Hezbollah and the Russian air force, reportedly cleared 1,200 km2 of territory in the Homs-Deir ez-Zor region, killing at least 50 ISIL militants. In addition, government forces seized 2,500 square kilometers of ISIL-held territory along the Iraqi border on 21 June. However, ISIL attacks from the Deir ez-Zor desert on government positions around the Euphrates River continued during the entire summer, during which dozens of Syrian Army soldiers were killed; some estimates by the local observers were that up to 1,000 ISIL fighters were still hiding in the Homs-Deir ez-Zor desert pocket.

On 31 August, the Syrian Army and the pro-government Palestinian militia Liwa al-Quds launched a large operation. ISIL fell back far into the desert to try and escape the offensive. However, ISIL attacks on 2 September, near Mayadin and south of Deir ez-Zor left 22 pro-government and at least 8 ISIL fighters dead.

During an offensive between 10 and 11 September, the Army advanced 30 kilometers into ISIL territory. Between 14 and 15 September, the Army advanced against the ISIL pocket, nearly splitting it. By the end of 15 September, the military had reportedly captured three towns. By this point, since the offensive started on September 10, 10 pro-government and 8 ISIL fighters had been killed. On September 16, ISIL launched a large counter-offensive, recapturing all of the territory it had recently lost and killing over 25 soldiers. However, on 17 September, the military once again captured all the areas it had lost the previous day, after launching a counterattack against ISIL forces. The Army continued to advance against ISIL as of 19 September, amid fighting that left another nine ISIL fighters and two government soldiers dead.

On 4 November, 11 people were killed in an explosion at a Syrian military base along the highway connecting Damascus and Deir ez-Zor, including six Russian private military contractors. The next day, during fighting east of Sukhnah five soldiers and eight ISIL fighters were killed.

2019
The death of three Russian soldiers was confirmed after they had gone missing during an ISIL ambush in February 2019. Several Syrian servicemen were also reported killed in the ambush. According to Russia, a group of more than 30 ISIL fighters who took part in the ambush were tracked down and “destroyed”. Around the same time, a Russian PMC was killed by a landmine in the region. At the end of February, the military started combing operations in the desert against the ISIL pocket and in early March, the Army conducted airstrikes against ISIL positions near Sukhnah, while preparations were taking place for the military to launch an operation in the area.

On 30 March, Syrian Army reinforcements were sent to the Palmyra countryside after several ISIL ambushes took place along the Palmyra-Deir ez-Zor highway over the previous two weeks, one of which on 24 March left five soldiers dead. Two days later, at the start of April, ISIL conducted a large attack on SAA positions near Palmyra which was repelled after airstrikes were conducted by the Syrian Air Force. By 3 April, more SAA reinforcements were sent in anticipation of a new ISIL attack on government positions. Meanwhile, a group of soldiers went missing following an ISIL ambush along the road near Haribshah on 31 March. On 11 and 18 April, two more ambushes took place with another military convoy going missing along the road between Palmyra and Deir ez-Zor, while an SAA unit was ambushed north of Al-Sukhnah. In addition, heavy fighting took place between 12 and 14 April, involving members of the Palestinian Liwa al-Quds militia.

On 21 April, ISIL captured the mountain town of Al-Kawm, forcing the Syrian Army and pro-government Palestinian militias to retreat. ISIL hit-and-run attacks continued into late June and fighting between 24 March and 23 June, according to the Syrian Observatory for Human Rights, left 161 pro-government and 53 ISIL fighters dead. Of the pro-government dead, 10 were Palestinian Liwa al-Quds militiamen, while nine were Iranian-led troops and two were Russians. Over 70 of the soldiers were killed in the month of April alone.