In recent months, the SDF forces have launched concentrated efforts, backed by airstrikes by the US-led coalition to rout the remaining fighters from the final patch of territory in Syria's eastern province of Deir Ezzor.
He said in the last ten days, SDF fighters had handled the battle "patiently" as more than 20,000 civilians were evacuated from the besieged enclave comprising two villages near the Iraqi border.
Bali said heavy fighting was going on inside the village of Baghouz on Sunday.
Up to 600 militants could still be inside, majority foreigners, said SDF spokesman Mustafa Bali.
There are an estimated 500 jihadists are holed up in the 3 square kilometre Baghouz area.
"There is of course a safe corridor and civilians are coming out daily, and this reduces their number in Baghouz until we can be sure the town is free of civilians".
The SDF has been on a crushing offensive to root out the IS from the eastern Euphrates region since last September.
The surprise announcement prompted the USA military to caution in a report published this month that the group "could likely resurge in Syria within six to 12 months and regain limited territory" if sustained pressure is not maintained.
During her visit to Iraq and meeting with French forces, Parly told them not to be distracted, despite the disconcerting announcement from their American allies that the USA troops will pull out of Syria.
"ISIS isn't finished yet", one commander said this week. In a statement, Under Secretary-General Vladimir Voronkov said despite a fall in "international attacks" in 2018, "this threat is increased by returning, relocating or released foreign terrorist fighters".
But the expected U.S. pullout has seen them grappling to mend ties with the Damascus regime, which is against Kurdish self-rule.
The armed group overran large parts of Syria and neighbouring Iraq in 2014, but a series of military offensives have reduced that territory to just Baghouz.
The SDF said it has not been in communication or agreed the ceasefire with IS.
Trump's surprise announcement in December that he was withdrawing American troops from Syria helped trigger the resignation of his defense secretary, Jim Mattis, and sent United States military officials scrambling to construct a withdrawal plan that preserves as many gains as possible.
Abdul Hamid al-Muhabash, the co-chair of the Democratic Autonomous Administration (DAA) in northeastern Syria, also expressed similar opinions as the SDF official.
The SDF managed, with the help of the USA, to defeat the IS in much of the areas it had controlled in the eastern Euphrates area.
The YPG fighter, who did not wish to be named, said spotting ISIS militants hidden among the thousands of fleeing civilians is proving hard.
Mushrooming black clouds rose over the embattled jihadist holdout in eastern Syria, as missiles and a warplane streaked through the sky.