Hayat Tahrir al-Sham (formerly Jabhat al-Nusra, the Syrian branch of al-Qaeda) and some other groups, including the Islamic Turkistan Party and Jaish al-Izza, have rejected a Turkish-Russian agreement to establish a demilitarized zone in the Syrian province of Idlib and the nearby areas, according to pro-militant sources.
On September 18, Russian Defense Minister Sergey Shoigu stated that work to establish a new security system in the Idlib de-escalation zone had started. He recalled that all heavy weapons have to be withdrawn from the demilitarized zone by October 10 and radical groups have to withdraw their forces by October 15.
So, Turkey and the Syrian-Iranian-Russian alliance have to force the militants to obey the agreement if they seek to enforce the demilitarized zone in time.
Pro-militant media outlets have already started spreading speculations that Damascus will not act up to its part of the agreement thus creating a media environment to justify actions of Hayat Tahrir al-Sham and its allies.