The US-supported, Kurdish-led Syrian Democratic Forces pressed their attacks on the last Islamic State enclave in eastern Syria on Monday.

US-led coalition warplanes supported the offensive with strikes, as more civilians fled the remaining ISIS-held villages near the Iraqi border.

The SDF has tried for months to clear the area, slowly advancing amid stiff ISIS resistance. The Forces, led by the Kurdish militia YPG, announced on Saturday that they were renewing the offensive against the enclave in Deir ez-Zor Province.

The head of the SDF media office, Mustafa Bali, said the Islamic State tried to counter-attack on Monday morning. He added that about 1,500 civilians had fled: “It seems there are still many civilians inside Baghouz. We are compelled to go cautiously and accurately in this battle.”

The SDF said that, before the latest offensive, more than 20,000 civilians had left the Baghouz area in 10 days. It estimates 400 to 600 ISIS fighters remain.

The offensive has been complicated by the politics around Donald Trump’s December order to withdraw the US troops backing the SDF. Turkish President Recep Tayyip Erdoğan, who has threatened military operations against the Kurdish-held 27% of Syria, is demanding the withdrawal of the YPG militia from a “safe zone” near the Turkish border and the handover of all American weapons given to the Kurdish faction.

Syria Daily, Feb 10: Erdoğan Steps Up Attack on US Over Kurdish-Held North

As the Pentagon and US officials push back the timeline for Trump’s withdrawal order, the head of US Central Command, Gen. Joseph Votel, said on Sunday that 10,000s of ISIS fighters remain in Iraq and Syria. He said that, despite its loss of almost all territory in Syria, the group retains the capacity for deadly attacks.