Daesh terrorists and their families detained in Syria pose a security threat but foreign governments have hesitated to repatriate their citizens.
The YPG-led SDF will allow up to 15,000 Syrians citizens leave a squalid camp it runs in the country's northeast, which holds displaced people and families of Daesh terrorists.
Syrian nationals will leave Al Hol camp and only foreigners will remain, AFP reported on Monday.
Dominated by the YPG, the SDF has been the main US partner in Syria and has driven Daesh out of a swathe of the country's north and east over the last four years.
The YPG is the Syrian offshoot of the PKK terror organisation.
Daesh fighters and their families detained in Syria pose a security threat but foreign governments have hesitated to repatriate their citizens.
Al Hol camp alone houses nearly 65,000 people, including about 28,000 Syrians, 30,000 Iraqis and some 10,000 other foreigners of many nationalities, according to UN estimates.
UNICEF said in August eight children had died in al Hol, where it said children from 60 countries were languishing and Covid-19 infections among camp workers had worsened conditions.
It was reported some Syrians had already left the camp and that the process would be sped up.
YPG-led SDF's presence in the region
The US and the YPG-led SDF have been collaborating in northern Syria since 2015 when Washington cobbled together the SDF to control the rich oil fields and fight the growing presence of Daesh in the region.
The US armed the SDF and stressed several times that the process was temporary and the supply of weapons and ammunition would be limited to what the group need to carry out specific operations against Daesh.
Despite evidence of the offshoot's ties to the PKK, an internationally-recognised terror group, US support for them in the region has not abated.
Turkey, the US and the EU have designated the PKK as a terrorist organisation.
In the PKK's 30-year terror campaign against the Turkish state, more than 40,000 people, including women and children, have been killed.
US President Donald Trump has repeatedly stated that Daesh is 100 percent defeated, but the US Department of Defense has already allocated $300 million to its future military projects in northern Syria for 2020.
The United States said last week all known Americans allegedly supporting Daesh and being held in Syria had been returned, some to face criminal charges. It urged European countries to account for their citizens.
Of the estimated 28,000 Syrians in al Hol camp, about 15,000 were from the mainly Arab areas of Raqqa and Deir Ezzor, which the YPG-led SDF captured from Daesh, and would be able to return if they chose to.