Several groups and committees in Syria including members of the Islamic Front - Jaish Al Mujahidin, Ajnad Sham and the Mujahidin shura council - issued a statement regarding the Islamic State's declaration of a new caliphate.
The statement said:
* the declaration is void mentally and legally.
* it seeks to divide Muslim countries.
* international and regional powers will take advantage of this declaration to directly intervene
for their interests.
* Syrian regime will gain legitimacy due to this declaration
The statement added that the Islamic State was trying to hide its crimes and reality by establishing Islamic state. The fighting groups in Syria would not change their attitude towards the Islamic State and would keep fighting it.
Link here, but it's in Arabic. http://justpaste.it/q324