"The Assad government now is being squeezed between these two groups"

NBC News reported in December that ISIS and Assad’s forces were mostly ignoring each other on the battlefield, focused on eliminating smaller rivals ahead of a possible final showdown.

The Assad regime was focused on stamping out the moderate and weaker opposition — and knew ISIS was doing so too. Now both are starting to engage in a “much more concerted way” because “there isn’t much of a moderate left,” according to Matthew Henman, head of IHS Jane’s Terrorism and Insurgency Center.

However, there is still one large, well-funded and well-armed obstacle acting as a thorn in both sides: the Army of Fatah, a coalition which includes the al Qaeda-linked Nusra front and recently seized control of Idlib from pro-government forces.

Analysts say the Army of Fatah also poses a longterm threat to ISIS as a competitor. Rumors are rife that the coalition is receiving funding from a variety of external actors — Saudi Arabia, Turkey and even Qatar — and Assad has had to rely on Hezbollah fighters for help in the Qalamoun Mountains to beat back the rebels.