Turkey has urged the United States to stop backing the Kurdish YPG in Syria. A spokesperson for President Recep Tayyip Erdogan told reporters that Kurdish fighters are using US-supplied weapons against Turkish troops trying to oust them from the Afrin region. <br/><br/>The spokesperson said Turkey cannot tolerate the Kurdistan Workers Party establishing some kind of a state structure along its border in Syria.Meanwhile, US Secretary of State Rex Tillerson has said, his country is willing to work with Turkey to address its legitimate security concerns in northern Syria.