A Syrian rebel fighter stands north of Aleppo and watches smoke billow from Afrin, where Kurdish People's Protection Units are facing off against Turkish and Turkey-backed fighters.
(OZAN KOSE/AFP/Getty Images) After days of bombarding Kurdish positions, Turkish forces and their Syrian rebel allies began a ground invasion into the northern Syrian region of Afrin. Dubbed Operation Olive Branch, the invasion targets the Kurdish People's Protection Units (YPG) that control the region. (ADEM ALTAN/AFP/Getty Images) Turkish President Recep Tayyip Erdogan gives a speech on Jan. 26. The YPG are central to the U.S. strategy against the Islamic State. Now Washington is afraid of a clash between its military and Turkish-backed forces. (BULENT KILIC/AFP/Getty Images) A soldier stands in front of Turkish army tanks preparing to enter Syria on Jan. 21. The majority of the advancing forces have come from north of Afrin, though rebel forces have launched their own assaults from the east. (OMAR HAJ KADOUR/AFP/Getty Images) A Turkey-backed Syrian rebel fighter launches a drone in the Afrin region, near the Turkish border.
