Speaking to Anadolu Agency in an interview, Abdulkarim al-Ubaid, who spoke on condition that his location is not revealed, said though he served as a senior SDF executive, he did not have a say in the group’s decision-making process. 

In October 2015, the PYD -- the PKK’s Syrian wing -- brought small groups of Arab fighters to form the SDF, promising to share weapons and logistics offered by the United States. 

Ubaid, whose al-Tahrir Brigade was part of the SDF until three weeks ago, said they were pressured by PYD/PKK militants when Arabs sought to gain control of their own lands. As a result of that pressure, they broke away from the SDF. 

“The PKK dominates the SDF; the decisions are being taken by the extremist organization,” he said. 

“The PKK does not only dominate the SDF but also the PYD,” Ubaid stressed. 

He insisted the groups composing the SDF were just a facade and that the SDF was just a “sheath” used by the PKK “to conceal their separatist goals and gain legitimacy in the territory they control”. 

Ubaid said one SDF commander -- Sahin Culu -- is a senior PKK commander.

He went on to note that Es-Sanadid forces and al-Tahrir Brigades -- two SDF factions -- were given a backseat within the force. 

"SDF commanders were annoyed by the sympathy the al-Tahrir Brigade gained in Tel Abyad,” he said. “They responded to our efforts to establish an Arab front -- with a view to building a balance between these forces -- by putting pressure on us.” 

"That is why we had to retreat," Ubaid said.