Syrian al-Qaeda and the Kurds

Continuing the theme that the al-Qaeda-like groups in Syria are now battling against their fellow anti-Assad forces, a Kurdish rebel official named Redur Khalil explains the battle his militias are waging against Jabhat al-Nusra and ISIS:

Since Jul. 16 our forces have been constantly engaging in clashes with Al Qaeda-linked groups like Jabhat al Nusra and, especially, the ISIS – Islamic State of Iraq and the Levant – all across our territory.

These terrorist groups have not only killed and abducted Kurdish people and displaced civilians from their villages but also looted their properties, homes and places of work. After heavy clashes in areas like Afrin, 340 km north of Damascus, and Serekaniye, 506 km north of Damascus, we have pushed them down to Til Kocer, 840 km northeast of Damascus on the Syria-Iraq border.

Khalil claims that these groups are supported in their efforts by Turkey, which would prefer not to have a strong Kurdish autonomous area in Syria to go with the one in Iraq.  If those allegations are true, then it is short-sighted on the Erdogan government's part, since a Syria dominated by salafi militants poses the risk of long-term instability on the border from which the Kurds are likely to benefit anyway.  My best guess is that there is simply a confluence of both the Turkish army putting pressure on the armed Kurdish groups and the al-Qaeda types waging steady battles, but not actual support from one to the other.