People fleeing the area have included surrendering Islamic State fighters, their family members, other supporters of the group, civilians caught up in the conflict and captives of the jihadists.
AFP journalists at an SDF post inside Baghouz village, the last IS redoubt, heard sporadic rounds of mortar fire and US-led coalition planes overhead.
The SDF recently gave the holed up Islamic State terrorists an ultimatum to surrender or prepare for battle, eventually relaunching their offensive in Baghouz a day later after they refused to give themselves up.
SDF commander Adnan Efrin told Kurdistan 24 on Sunday that the Kurdish-led forces had rescued tens of thousands of civilians during the past month with thousands of Islamic State members surrendering as well.
"Around 1,300 terrorists and their families surrendered to our forces today amid our operations against the terrorist Daesh organization", Mustafa Bali, a spokesman for the Syrian Democratic Forces (SDF), said in a tweet on March 14, using an alternate name for IS.
The attackers wearing "women's clothing detonated suicide vests while mixed with other members of Daesh [ISIS] & their children", explained an online statement from the worldwide US-led anti-Islamic State coalition.
IS launched three suicide attacks Friday outside Baghouz, killing six people among those fleeing the crumbling jihadist bastion near the Iraqi border.
It added: "The SDF takes all precautions to protect human life".