"... TAL ABYAD, Syria — Two Syrian rebel groups – one seeking an elected civil government, the other favoring the establishment of a religious state – are battling each other in the city of Tal Abyad, on the border with Turkey, in a sign of the tensions that are likely to rule this country if the government of President Bashar Assad falls.
Four people were killed Sunday in fighting here between the Farouq Battalions, which favors elections, and Jabhat al Nusra, or the Nusra Front, which the United States has declared an al Qaida-affiliated terrorist group....
The rivalry between the groups is a reminder of how divided Syria’s rebel factions are and how inaccurate it is to refer to the anti-Assad forces as if they were a single group, with a single goal. Indeed, while news stories for months often referred to rebels as the Free Syrian Army, that term is more an idea than an organization. Instead, the rebel movement comprises dozens of groups whose ideologies have only one common goal: the toppling of the Assad regime.
“They call us kufar,” or non-Muslims, said Abu Mohammed, who leads a rebel brigade in Shadadeh. ... Members of other rebel groups increasingly liken Nusra to the Syrian government in its intolerance of any opposition, and they fear its spies. Nusra has detained secular activists who’ve spoken against it... “It seems we cannot deal with them peacefully,” he said. “So it seems inevitable we will fight them, whether it is before the regime falls or after.”