The Syrian Democratic Forces beat back an attack by pro-regime forces near the Euphrates River on Sunday.The raid began on Sunday morning and involved pro-regime forces that often consist of groups of militias, many of them connected to Iran.According to reports, these pro-regime forces operating from Deir ez-Zor struck north toward the villages of Junaynah and Maishiyah, seeking to capture a small part on the SDF-controlled eastern side of the Euphrates River. These villages lie in a small bend of the river, and the regime forces sought to grab the bulge created by the bend, advancing over one kilometer of territory.The US-led coalition that partners with the SDF in the war against Islamic State said it could confirm that the attack took place in the morning.“The coalition used established deconfliction channels to deescalate the situation,” a statement by the Combined Joint Task Force: Operation Inherent Resolve said. “The coalition remains committed to our SDF partners in the campaign to defeat Daesh [ISIS].”Wladimir Van Wilgenburg, a journalist, shared a comment from SDF commander Polat Can on Twitter: “The regime’s militias, allies and mercenaries were defeated in the towns of Deir ez-Zor in the battle that broke out today when the regime attacked the area north of the Euphrates River.”This is the most important clash between the US-backed SDF and the regime since a February 7 raid by a large force of pro-regime fighters south of Deir ez-Zor. During that battle, the coalition used air strikes to beat back the attack, killing more than 100 of the pro-regime forces. Later it emerged that there had been casualties of Russian contractors who have been serving alongside the regime forces.Sunday’s clash appeared less significant and less large. But it continues to show that President Bashar al-Assad’s Syria and its allies want to test the coalition and its SDF partner.