At least 73 people, mostly rebels, were killed yesterday when the Islamic State group carried out a suicide car bombing in Syria's al-Bab near the Turkish borders.<br/><br/>Activists said the IS bombing targeted a security compound of the Turkey-backed rebels in the town of Susian northwest of al-Bab, which was the largest IS-held city near the Turkish borders.<br/><br/>The bombing came as retaliation against the Ankara-backed militants, who succeeded, along with the Turkish forces, to dislodge IS from al-Bab on Thursday. The withdrawal of the IS from al-Bab came after 100 days of battles against the Turkish forces and allied Syrian rebels fighting in an operation called the Euphrates Shield.