US-backed Syria force says time up for IS 'to surrender'

US-backed forces said Sunday time was up for Islamic State group jihadists hunkering down in their eastern Syrian holdout and an assault was imminent.

"The timeline (we gave) ISIS to surrender themselves is over," Syrian Democratic Forces spokesman Mustefa Bali said on Twitter, using another acronym for IS.

"Our forces have received orders for military action to finish off what is left of the terrorists in Baghouz," a village near the Iraqi border, he said. "The assault will start at any moment," he told AFP.

The SDF, who are backed by air strikes of the US-led coalition, have slowed down their months-long campaign against the jihadists in recent weeks to allow civilians out from the shrinking enclave.

Thousands of dust-covered women, children, and men have trundled out of the village of Baghouz in the past weeks, but that exodus has slowed to a trickle in recent days.

Suspected jihadists have also been detained after exiting among the crowd.

On Saturday, "only about 100 people left, including three Chinese Uighurs and three Moroccan women", Bali told AFP earlier.

The extremists once ruled over millions in a swathe of Syria and Iraq, but they have since lost all that land except for the riverside encampment in Baghouz.

The total capture of the encampment by the SDF would be a symbolic blow to IS, and mark the end of the cross-border "caliphate" it proclaimed in 2014.