An Iraqi security official says the U.S.-backed Syrian forces fighting the Islamic State group in Syria have handed over more than 150 Iraqi members of the group to Iraq.

The official says the IS militants were handed over to the Iraqi side overnight, and that they were now in a "safe place" and being investigated.

The official spoke on condition of anonymity in line with regulations.

The handover comes as the U.S.-backed Syrian forces are involved in a standoff over the final IS-held sliver of land in southeastern Syria, close to the Iraqi border amid the extremists' imminent territorial defeat.

Earlier this month, Iraqi Prime Minister Abdul-Mahdi said Iraq will take back all Iraqi IS members, as well as thousands of their family members.