Syrian civil war: The Syrian Democratic Forces opened the Second Battle of Raqqa, the final phase of the Raqqa campaign, capturing the de facto capital of the Islamic State four months later. Syrian Democratic Forces: The Syrian Democratic Forces (SDF) was a Kurdish-led coalition of left-wing ethnic militias and rebel groups, which served as the official military wing of the Democratic Autonomous Administration of North and East Syria from 2015 to 2026. Founded on 10 October 2015, the stated mission of the SDF was to create a secular, democratic, and federalized Syria. The SDF was opposed by Turkey, who viewed the group as an extension of the Kurdistan Workers' Party (PKK), which is internationally designated a terrorist group. June 6, 2017. Wiki link