The UK-based group said the prisoners were among 1,350 civilians and fighters that Daesh had been holding in territory near the Iraqi border.
The terrorist group controls a shrinking strip of land east of the Syria’s Euphrates River around the town of Hajin, which US-backed forces entered this month.
The Syrian Democratic Forces (SDF), led by the Kurdish YPG militia, has battled Daesh there for several months.
SDF commander-in-chief Mazloum Kobani told Reuters last week that at least 5,000 Daesh members remain holed up in the enclave, including many foreigners who appear ready to fight to the death.
Daesh’s self-proclaimed caliphate has crumbled after different offensives across Iraq and Syria, though its fighters still operate in the desert border region and mount attacks.
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