Turkish President Tayyip Erdogan (R) meets with U.S. Defense Secretary Jim Mattis at the Presidential Palace in Ankara, Turkey, on Aug. 23, 2017. Turkish President Recep Tayyip Erdogan expressed Turkey's unease over U.S. support to the Syrian Kurdish People's Protection Units (YPG) during his meeting with U.S. Defense Secretary Jim Mattis on Wednesday. (Xinhua/Turkish Presidential Palace)
