Turkey on Thursday slammed the United States for its claim that the SDF has no ties to the PKK terror organisation.
US Central Command had re-tweeted a statement by the Syrian Democratic Forces (SDF) alliance, which includes the YPG, saying it was not part of the PKK.
Presidential spokesperson Ibrahim Kalin responded on Twitter.
Is this a joke or @CENTCOM has lost its senses? Do you believe anyone will buy this? The US must stop trying to legitimize a terrorist group
— Ibrahim Kalin (@ikalin1) January 12, 2017
Turkish President Recep Tayyip Erdogan on Thursday said "nobody" had the right to claim that the YPG has no links with PKK terrorists in Turkey.
"Those who were shedding blood under the Daesh flag until yesterday have now emerged with a PYD, YPG identity. Nobody has the right to claim they have nothing to do with the PKK," Erdogan said at a meeting in Ankara.
Turkey views the YPG as the Syrian extension of the PKK terror group, which has waged a three-decade insurgency against the Turkish state and is considered a terrorist organisation by Ankara, the United States and the European Union.
Turkey considers the YPG and PYD to be terrorist organisations because of their affiliation with the PKK.
The US considers the YPG/PYD to be a "reliable partner" on the ground in Syria against Daesh and continues to support them in the field.
However, in testimony before a Senate panel in April 2016, US Defence Chief Ashton Carter admitted the PYD and YPG were aligned with the PKK when Senator Lindsey Graham directly asked him.