The SDF are advancing on two fronts — Baghuz and Hajin — the local force announced in a statement on Sunday.
"In the evening, engagements continued on several points in this front, where the terrorist organization tried to regain the points and areas that they lost, and due to that [a] number of terrorists were killed," read the SDF statement on the Baghuz advance.
The forces advanced a kilometer and have established more than a dozen defensive positions. The SDF have faced a number of ISIS counterattacks in the fight for Hajin.
Additionally, "the engineering units of our forces dismantled a number of mines that [were] laid by terrorists."
On the Hajin axis, the SDF "launched a violent attack on the terrorists’ positions and fortifications." Progress was described as "good."
The forces also had to detonate or dismantle mines and booby traps left by ISIS. SDF has established nearly three dozen defensive positions, according to its statement.
The Syrian Observatory for Human Rights detailed that the SDF force is comprised of Jaysh al-Thuwar (an Arab force), Jabhat al-Akrad (a Kurdish force), al-Shaitat (an Arab force), and the Deir ez-Zor and Manbij Military Councils (mixed forces).
There was no direct mention of the predominately Kurdish Peoples' Protection Units (YPG) participating in the fight, although the group has been allied with the other forces under the SDF umbrella throughout the ISIS conflict in northeast Syria.
The UK-based monitor added that the SDF now controls 70 percent of Hajin following the clashes. It also reported "intensive mines" left by ISIS.
In late October and November the US-led international coalition was reportedly unable to fully provide air support because of poor weather conditions.
The Observatory said coalition war planes conducted bombardments on Saturday morning.
The SDF's Operation Roundup began on May 1 with the goal of clearing ISIS from east of the Euphrates.
