Rebels led by Jaysh al-Islam and various Free Syrian Army factions repelled the assault and dozens of ISIL fighters were killed.

[12] On 17–18 September, ISIL forces launched a successful assault against rebel positions at Badiya, killing four and capturing forty defenders,[13] while losing two vehicles in return.

[19] On 26 September, unknown gunmen attempted to assassinate Harith Siwar, commander of Jaysh al-Islam in the Eastern Qalamoun Mountains.

[3] On 29 September, ISIL forces launched a new attack in the eastern Qalamoun Mountains, leading to heavy clashes with the rebel defenders.

[20] In the night of 1–2 October, ISIL fighters stormed eastern Jabal al-Afa'i amid heavy fighting with FSA forces.

[28] On 29 December, FSA forces launched an offensive toward ISIL lines in the eastern Qalamoun and captured five villages.