"Akar and Dunford have discussed the return of weapons passed to the YPG terrorists and also fight against terrorist organisations including the IS.* Akar has stressed the importance of speeding up the implementation of the Manbij road map and of immediate withdrawal of the YPG terrorists from the region. He noted that Turkey was determined to take all necessary measures to ensure its border security and regional stability," the Turkish defence ministry statement read.
In mid-December 2018, Turkish President Recep Tayyip Erdogan said that Ankara was ready to launch a military operation against the YPG if the United States did not compel them to abandon territory they had taken (from Daesh terrorists) to the west of the Euphrates River. Trump agreed to withdraw US troops supporting the YPG from the city. In late December, however, the Syrian government sent troops to Manbij "after Kurdish fighters appealed to Damascus for help against the threat of attack by Turkey in the face of the withdrawal of US troops from the area", according to The Guardian.
Ankara considers the YPG the Syrian branch of the PKK, which is listed as a terrorist organisation by Turkey, the EU and the US, according to Turkey's Hurriyet Daily News.
Turkey believes that the YPG presence near its border threatens its national security. Turkish and US troops are operating in Syria without the consent of Damascus, but US forces will leave the country once Daesh is defeated and Kurdish fighters are assured protection, US national security adviser John Bolton announced on Sunday.
*Daesh (ISIL/ISIS/Islamic State/IS), a terrorist group banned in Russia and a wide number of other countries.