After the capture of Manbij by the Syrian Democratic Forces in August 2016, al-Bab was reported to be the next objective of the Syrian Democratic Forces (SDF) campaign. In December 2016, al-Bab came under an attack by Syrian rebels backed by Turkey. Turkish air strikes on 21 December destroyed 67 Islamic State targets; 59 Turkish soldiers and over 200 rebels were reported killed. Al-Bab was a strategically important town for Turkey because it did not want the two SDF regions to link up. On 9 February 2017, a Russian air strike killed three Turkish soldiers by mistake. On 23 February 2017, al-Bab was captured by Turkish-backed rebels, becoming a part of the Turkish buffer zone.