'There is still more'

US-backed fighters have been hoping for weeks that the final day has come for the Islamic State group's "caliphate", but its last tiny sliver of land just won't seem to empty.

Tens of thousands of dust-covered women, children and men have streamed out of the ragged tent encampment in the Syrian village of Baghouz since December -- and despite that exodus they still keep on coming.

The numbers have flummoxed the Kurdish-led forces and bogged down their offensive to finish off the once sprawling proto-state.

"When we began the operation we knew there would be civilians, but not in such a big number," Adnan Afrin, a spokesman for the Syrian Democratic Forces, said Thursday.

In recent days thousands more men and women -- including those who once flocked to join IS from across the globe -- left the IS pocket.

That upended assumptions that few families remained holed up in Baghouz and those who refused to leave or surrender were choosing to die there.

"They're coming from underground... they're never-ending," said one SDF official.

The International Rescue Committee on Friday said as many as 12,000 people from Baghouz have arrived in one camp for non-combatants in northeast Syria over the past 48 hours, including some 6,000 people on Thursday alone.

The women trucked out of the bastion this week gave drastically varying figures on the holdout families that remain in the bombed-out and besieged jihadist bastion.

More than 55,000 civilians have arrived in the Kurdish-run Al-Hol camp since December, according to the International Rescue Committee.

Aid group Free Burma Rangers has come in close proximity to the camp in recent days and its head, David Eubank, told AFP some two thousand people could remain inside.