SDF, according to Abdul-Rahman, is progressing in the east of Deir Ezzor, besieging the remnants of ISIS.
The troops face a problem with the detention of former ISIS members, as around 1,000 members, including extremist ones, are detained.
Coming from more than 40 countries, their governments refuse their return.
Their wives and children live in a camp controlled by SDF.
Speaking to Al-Arabiya TV channel, Riyadh Dirar, the co-president of SDF, said the small groups of ISIS and its dormant cells is very complicated, urging exceptional intelligent cooperation as they are located everywhere.
SDF currently has a major security mission, according to a military source, who said the prevention of extremists infiltration it convoys of civilians is very complicated.