On 5 July 2013, units of the FSA's 33rd Infantry Division were deployed to the town of al-Dana in Idlib Governorate after ISIL fighters opened fire on civilian anti-ISIL protesters.

[36][37] The conflict was renewed over Azaz in early October 2013,[38] and in late November ISIL captured the border town of Atme from the Hawks of Islam Brigade.

In the first few days of the conflict, al-Qaeda's al-Nusra Front and Ahrar al-Sham brokered a ceasefire agreement with ISIL in the city of Aleppo and its northern countryside.

[61] In Raqqa, the hospital was abandoned, bodies were lying in the central square and there was no power or water leaving the city "completely paralyzed", according to an opposition activist.

[62] The head of the al-Nusra Front, Abu Mohammad al-Golani, confirmed that fighting had taken place between his organization and ISIL and called for mediation and an end to the "infighting.

[67] In Idlib province, ISIL opened fire on a demonstration in Kafartkharim and besieged several field clinics, and stormed one of them, searching for rebels injured earlier in the morning during clashes in Atarib.

[77] On 12 January, it was confirmed that rebel forces had captured the eastern part of Saraqeb with the local ISIL commander surrounded with his fighters in the center of the town.

[84] Another mass execution of prisoners was also reported near the village of Kantari, about 80 kilometers north of Raqqa, when ISIL killed 46 captured fighters of the Ahrar ash-Sham rebel group.

[13] Three days later, the Tunisian ISIL deputy Emir for the Raqqa province and three other fighters were killed by a roadside bomb, while rebels captured the village of Kafrnaya in Aleppo.

[117] The next day, the ISIL emir Abu Mouhammad Al-Massri was assassinated by the FSA affiliated Al-Raqqa Revolutionaries Brigade in the Raqqa's Tal-Dikan area, near the village of Sarreen.

[120] On 27 March, ISIL launched an operation against Al-Nusra and allied forces at the al-Jafra oil field and the Koniko gas factory in Reef Deir Izzor.

[135][136] ISIL also gained control of Syria's largest oil field, al-Omar in Deir ez-Zor province, after Al-Nusra forces fled the facility.

[151] Additionally, by 18 August opposition sources had reported the mass defection of the Aleppo-based Khaled Rashed, Green and Tawhid-e-jihad brigades to the Islamic State.

Fighters from the US trained "Division 30" were reported to have entered Syria and taken positions in Azaz with the intention of coordinating with rebel groups to push back ISIL.

[172] In May 2014, ISIL launched an offensive against Al-Nusra and allied groups in Deir ez-Zor Governorate, seizing oil wells and leaving hundreds dead on both sides.

[188] On 1 April 2015, ISIL, reportedly facilitated by Nusra's local wing, stormed Yarmouk refugee camp in the area outlying central Damascus.

[196] On 22 April, ISIL captured wide parts of al-Mahsa area, in the eastern Qalamoun, and cut off the rebel supply line between Jordanian border and the Syrian al-Badia.

[199] Between 27 and 29 April 2015, fighting raged south of Quneitra city, near the Israeli-held Golan Heights, between an ISIL-linked rebel group Jaysh al-Jihad on one side and al-Nusra and FSA fighters on the other.

On 29 April, fighting also erupted in Daraa province between al-Nusra and the Yarmouk Martyrs Brigade, which was accused the previous month of also pledging allegiance to ISIL.

[211] In June Al-Mu'tasim Brigade formed an alliance with Liwa Ahfad Saladin and 6 other rebel groups in Mare' after breaking an ISIL siege on the town.

[250] Tel Astrh based points of the Jaysh Khalid ibn al-Walid were bombarded by the Southern Front Free Syrian Army's Hamza Brigade.

[253][254] Fighting resumed sporadically, with minor advances and retreats by the rebels' Nawa Operations Room in April, May, June and September 2017 (see In late 2017, ISIL launched its Northwestern Syria campaign (October 2017–February 2018).

On 9 October, ISIL attacked HTS in the northeastern Hama countryside near the southern administrative border of the Idlib Governorate, having infiltrated the area via government-controlled territory.

In 2014, it was reported that Jund al-Aqsa was receiving continuous funding from wealthy private Gulf donors for their refusal to attack ISIL, part of which was the reason for their rift with al-Nusra Front and Ahrar al-Sham.

[258] On 23 October 2015, Jund al-Aqsa left the Army of Conquest, because it had misgivings about fighting against the Islamic State of Iraq and the Levant, while reaffirming its loyalty to al-Qaeda.

[260][261] SOHR claimed that Jund al-Aqsa joined the 2016 Idlib Governorate clashes and established checkpoints in support of JaN.[262] According to the 13th Division's media wing, their position was overran and 4 of their fighters were killed.

[265][better source needed] During the clashes in Idlib, the group aided al Nusra Front by sending them two suicide bombers of Kuwaiti and Saudi origins.

[274] Within the past three years, the group has assisted al-Qaeda in toppling the Syrian Revolutionaries Front and the Hazzm Movement, two key Western-backed rebel organizations in Syria, as well as weaken a third called Division 13.

[282] It was rumored that Liwa al-Aqsa pledged allegiance to the Islamic State of Iraq and the Levant, sparking the clashes with Tahrir al-Sham, known as a staunch ISIL opponent.

[291] On 22 February, the last of Liwa al-Asqa's 2,100 militants left their final positions in Khan Shaykhun, with unconfirmed reports in pro-government media that they were to join ISIL in the Ar-Raqqah Province after a negotiated withdrawal deal with Tahrir al-Sham and the Turkistan Islamic Party.