According to an article published today in the Wall Street Journal,Western backed rebel opposittion forces, fighting Assad's regime are facing a three front war:
"An al Qaeda spinoff operating near Aleppo, Syria's largest city, last week began a new battle campaign it dubbed "Expunging Filth."
The target wasn't their avowed enemy, the Syrian government. Instead, it was their nominal ally, the U.S.-backed Free Syrian Army.
Across northern and eastern Syria, units of the jihadist group known as ISIS are seizing territory—on the battlefield and behind the front lines—from Western-backed rebels.
Some FSA fighters now consider the extremists to be as big a threat to their survival as the forces of President Bashar al-Assad. "It's a three-front war," a U.S. official said of the FSA rebels' fight: They face the Assad regime, forces from its Lebanese ally Hezbollah, and now the multinational jihadist ranks of ISIS.
Brigade leaders of the FSA say that ISIS, an Iraqi al Qaeda outfit whose formal name is the Islamic State of Iraq and al-Sham, has dragged them into a battle they are ill-equipped to fight.
In recent months, ISIS has become a magnet for foreign jihadists who view the war in Syria not primarily as a means to overthrow the Assad regime but rather as a historic battleground for a larger Sunni holy war. According to centuries-old Islamic prophecy they espouse, they must establish an Islamic state in Syria as a step to achieving a global one".