The ISIS faced final territorial defeat on Saturday as the US-backed Syrian force battling the militants said it was closing in on their last bastion near the Iraqi border, capping four years of efforts to roll back the group. Mustafa Bali of the Kurdish-led Syrian Democratic Forces says fighters are advancing on two fronts amid intense fighting with the extremists in the last area they control. Bali tweeted Saturday that "heavy clashes" are taking place in the area on the east bank of the Euphrates River. He said three SDF fighters were wounded. The SDF on Friday evening resumed military operations to liberate the last piece of territory held by ISIS in the province of Deir Ezzor after evacuating thousands of civilians and hostages who had been besieged inside. The Associated Press quoted Zana Amedi, an SDF commander, as saying that "an active ground force" is advancing into ISIS-held territories as the extremists resort to sniper fire and booby-traps. While the fall of Baghouz, an eastern Syrian village on the bank of the Euphrates River, would mark a milestone in the campaign against ISIS, they remain a threat, using guerrilla tactics and holding some desolate land further west. An array of enemies, both local and international, confronted ISIS after it declared a modern-day "caliphate" in 2014 across large swathes of territory it had seized in lightning offensives in Syria and neighboring Iraq. Thousands of ISIS fighters and followers, who had retreated to Baghouz as the group was gradually driven out of those lands, have poured out of the tiny cluster of hamlets and farmlands in Deir Ezzor province over the last few weeks. Their evacuation held up the final assault until Friday evening when the SDF said it had advanced and would not stop until the militants were defeated. "We expect it to be over soon," Mustafa Bali, a spokesman for the Syrian Democratic Forces (SDF) told Reuters. The SDF commander-in-chief said on Thursday that his force would declare victory within a week. He was later contradicted by US President Donald Trump, who said the SDF had retaken 100 percent of the territory once held by IS. Washington has about 2,000 troops in Syria, mainly to support the SDF in fighting ISIS. Trump announced in December he would withdraw all of them, but the White House partially reversed itself last month, saying some 400 troops would stay. Some 40,000 people bearing various nationalities have left the militants diminishing territory in the last three months as the SDF sought to oust the militants from remaining pockets. The number of evacuees streaming out of Baghouz surpassed initial estimates of how many were inside. An SDF commander told Reuters on Thursday that many of the people leaving the enclave had been sheltering underground in caves and tunnels.