The American-led intervention in Syria has been ongoing since 22 September 2014, after the United States intervened in the Syrian Civil War against the Islamic State. From May 31 to August 27 2016 the Syrian Democratic Forces, a coalition of anti-ISIL militias led by the YPG, successfully campaigned to capture the city of Manbij and its outskirts in Aleppo governorate. US air support played a key role in this offensive, with US airstrikes hitting Islamic State militants in and around the city.