The US-led force has been operating in Iraq for 12 years to dismantle ISIS networks which had threatened to take over the region and plunge it into instability.
Baghdad has recast 30 September — originally a hard deadline for armed factions to surrender an estimated 6 million weapons — as the start of a regulatory process, as Kataib Hezbollah and Harakat al-Nujaba refuse to hand over what they call "resistance weapons".
The suspects were part of a group of 47 French nationals transferred last year from Syria to Iraq, where numerous suspected IS members were already being held.