When the extremist group known as the Islamic State took control over Palmyra, an ancient city nestled deep in the Syrian desert, in late May, it was a clear strategic defeat for the government of President Bashar al-Assad. As the battles neared the astounding historical ruins of Palmyra, the Islamic State got all the media attention it could hope for and Assad’s weakness was exposed to the world. By breaking open and destroying the infamous Palmyra Military Prison, which was for decades the dark heart of the Syrian regime’s system of coercion, the Islamic State has reasserted its anti-Assad credentials in the eyes of many Syrians.

This winter, the Islamic State suffered severe losses during the long battle for the Kurdish town of Kobane on the Syrian-Turkish border and it continues to lose territory to the Kurds in northern Syria. Even so, the jihadi group has been able to advance elsewhere in Syria. And despite structural obstacles to its expansion and a string of defeats in Iraq, it recently captured the provincial capital of Ramadi, while Islamic State forces retreating from the northern city of Tikrit have turned to wreak havoc on the Baiji oil refinery. However, it is Syria that presents the most promising arena for the Islamic State, which seems to be aiming for high-profile victories in the lead-up to the holy month of Ramadan and the one-year anniversary of its unilateral declaration of a “caliphate” in late June 2014.

Exploiting the recent weakening and territorial losses of the Syrian government, the Islamic State has begun to pressure Hasakah City, north of Deir Ezzor. In parallel it has launched a new offensive in Aleppo, striking government forces in the Sheikh Najjar industrial area and pushing toward the key Bab al-Salam crossing on the Syrian-Turkish border near Azaz, to cut rival Sunni insurgents off from foreign support. If this succeeds, it could be of immense significance for the future of the war. But the taking of Palmyra, the central hub of Syria’s desert road network connecting southwest to northeast, has also opened new possibilities

Deir Ezzor: Battle for the East

By taking Palmyra and the smaller town of Sokhna, further northeast, the Islamic State has secured its stranglehold on the city of Deir Ezzor, Assad’s last remaining stronghold in the eponymous province.

The government and the Islamic State have been wrestling for control over Deir Ezzor virtually nonstop since summer 2014, and, before that, Assad fought other rebel factions in the area. Rather than accept defeat after losing the entire Euphrates region, the Syrian regime has invested enormous resources in trying to maintain its foothold in Deir Ezzor, perhaps sensing that its loss would spell the symbolic end of Assad as a national actor with potential to reclaim all of Syria.

Deir Ezzor’s southern neighborhoods have been transformed into a heavily fortified garrison by a combined Syrian army, security, and tribal militia contingent ensconced in the Joura district, around the military airport, and in other key areas. The president has even dispatched two of his best-known commanders to the besieged city, Brigadier Generals Issam Zahreddine and Mohammed Khaddour, thereby raising the stakes to a point where its fall would mean a devastating loss of face.

For the Islamic State, exploiting its victory in Palmyra to tighten the seige on Deir Ezzor and ultimately capture it is likely to be a high-priority goal.The group recently pushed deeper into Deir Ezzor, seizing much of Sakr Island in the Euphrates. And a detailed opposition report published in mid-May 2015 on the Islamic State’s military organization in Wilayet al-Kheir—the group’s label for the Deir Ezzor Governorate—notes that it continues to train new recruits in the area.

Many Targets to the West and South

Other options are on the table, too. From Palmyra, the jihadis can threaten a range of important targets and keep regime forces under pressure along a broad front. To the northwest, Islamic State forces are already pressing into the Salamiya area, threatening the Ismaili community there, but also—and most crucially—adding pressure to Assad’s last remaining supply route to Aleppo.

Moving down the front, the Islamic State could try to connect with its fighters in the Homs region, which is under Assad’s control but where the remaining rebel enclaves seem susceptible to Islamic State infiltration and influence.

Southwest of Palmyra, the retreat of regime forces has pushed back their defense line and made it easier for the Islamic State to use the eastern Qalamoun region as a launch pad for raids on the Homs–Damascus highway. Defending it is now crucial for the regime’s ability to maintain movement between the capital and the coastal region. Further west, the western Qalamoun region allows for access to the Lebanese borderlands. Opposition media now claims that the Islamic State has brought in reinforcements from the north to fight against rebels in the eastern Qalamoun, south of the Palmyra-Homs line, where it has taken al-Mahsa village and is approaching the town of Ruheibeh.

Looking southward, the eastern Ghouta suburbs of Damascus are a hard target for the Islamic State, due both to the government siege and to the strong position of the militant Army of Islam, which is led by Zahran Alloush, a Sunni Islamist who is fiercely opposed to the Islamic State. But the Syrian capital is too big a prize for the Islamic State to ignore: even if it can’t take the city, its ability to pose a threat reinforces its credibility and enhances its political stature.

Lastly, south of Damascus, the Druze towns of the Sweida Governorate may also prove a hard nut to crack, but the prospect of battling “apostates” may still attract the Islamic State. More immediately, however, the Islamic State may bypass Damascus and Sweida in order to infiltrate forces into the contested Houran region. The Jordanian border and the Golan Heights close to Israeli-occupied territory are highly attractive for the Islamic State. Other rebel factions know this, and have been hunting and killing Islamic State supporters for fear of fifth-columnist action. Battles are currently ongoing in the southwestern corner of Syria, where the pro-Islamic State militants of the Yarmouk Martyrs Brigade are under heavy pressure from other rebels.

Seizing or Destroying Energy Infrastructure

The Palmyra area is also important for its energy infrastructure. The Islamic State has reportedly captured the gas fields to the east of Palmyra, and pressures those to the west that remain in government hands. However, while the Islamic State has profited greatly from its oil fields in eastern Syria, gas production involves very different technical challenges and the Islamic State will not be able to exploit the fields economically without highly specialized equipment and suitable means of transportation. But capturing gas fields as well as related processing plants and stations is still an effective form of economic warfare: losing access to these facilities means a net loss for the regime, which relies heavily on gas for electricity generation.

Similarly, the Islamic State has reportedly seized two phosphate mines near Palmyra, but extraction and export may prove very difficult. As of early June, the main effect has been to deny the Syrian government any income from these facilities, in the same way the assault on Baiji in Iraq denied Baghdad the use of refining capacity that provides half of its national needs.

The governments in both Syria and Iraq are under tremendous economic strain, with oil prices slipping, electricity infrastructure failing, and Iran appearing to waver over how much support it can afford to extend to its allies. By systematically targeting or seizing control over the Syrian power infrastructure, the Islamic State aggravates the crisis in government-controlled areas and gains important leverage over electricity-dependent communities, thereby positioning itself to further exploit the weakening of Assad’s government.

Read Also: Yezid Sayigh "The War Over Syria's Gas Fields", June 8, 2015.