The Syrian Democratic Forces (SDF) advanced in the "Islamic State of Iraq and Syria" (ISIS) group's last bastion in eastern Syria, confining holdout extremists to a tiny pocket on the edge of al-Baghouz village, AFP reported Tuesday (March 19th).

The SDF said those ISIS fighters who had not yet surrendered had been forced out of their main encampment and cornered into a very small area on the banks of the Euphrates River.

"SDF is in control of the ISIS encampment area in al-Baghouz," spokesman Mustafa Bali said on Twitter in English.

But SDF fighters have not taken up positions in the so-called encampment, a jumble of mangled vehicles, makeshift berms and tents on the edge of al-Baghouz.

"This is not a victory announcement, but a significant progress in the fight against ISIS," Bali said.

After another night of fighting and the surrender of yet another batch of extremist fighters, the few acres of land controlled by ISIS shrank further.

It is unclear how long the unknown number of holdout extremists could last but Bali said some of them were still fighting back.

"Clashes are continuing as a group of ISIS terrorists who are confined into a tiny area still fight back," he said.

AFP reporters in al-Baghouz saw ISIS elements moving across the edges of the now mostly deserted encampment, and fighting taking place in an area closer to the river.

Backed by warplanes from the international coalition, the SDF launched their final assault on ISIS in al-Baghouz on February 9th.