The mission began with US forces transporting 150 ISIS fighters from a detention facility in northeastern Hasakah province to a secure location in Iraq, with plans for up to 7,000 detainees to eventually be transferred to Iraqi-controlled facilities.

A fragile truce reached this week between the Syrian government and Kurdish-led fighters was seen as a blow by many Kurds in their hard-won fight for autonomy.

The huge al-Hol camp in northeastern Syria for years has posed an intractable problem — a destitute and increasingly dangerous detention site where ISIS ideology lives on.

The US on Thursday welcomed the Iraqi government’s decision to detain ISIS (Daesh) terrorists in secure facilities inside Iraq, citing recent instability in northeast Syria.