The Syrian Democratic Forces (SDF) on Tuesday (March 12th) said more people were surrendering from the last scrap of "Islamic State of Iraq and Syria" (ISIS) territory in Syria, after overnight air raids and shelling ravaged the group's outposts.

A ragged tent encampment in the eastern Syrian village of al-Baghouz is all that remains of the group's territory, AFP reported.

The SDF have been trying to crush holdout ISIS fighters for weeks but the mass outpouring of men, women and children from the riverside hamlet has bogged down their advance.

The Arab-Kurd alliance renewed its assault on Sunday after warning remaining ISIS fighters that time was up for surrenders.

Airstrikes and shelling have since pummelled al-Baghouz for two nights in a row, killing scores of fighters and prompting hundreds of extremists and their relatives to surrender.

"The objective of our advance is to terrorise ISIS fighters so they surrender, and for the civilians to come out," Ali Cheir, an SDF unit commander, told AFP from a rudimentary outpost inside the village.

The commander said the SDF had slowed its offensive after daybreak to allow for extremists and their relatives to turn themselves in.

"There are people handing themselves over now and we have completely halted fire so that they can surrender," he said.