The US and Russia have announced a ceasefire in Syria will come into effect on Feb. 27 but that will not include Daesh and al-Qaeda's Syrian arm, Nusra Front.
Erdogan said the ceasefire is positive in principle, but described as a "great lie" the notion that the Syrian Kurdish YPG militia, which is seen as a hostile insurgent force by Ankara, was being given support in Syria because it was fighting Daesh.
Turkey, which has been shelling positions of the Syrian Kurdish militia group People's Protection Units (YPG) since Feb. 13, insists that the group is the Syrian wing of the PKK and thus should be treated as a terrorist organization. Ankara has also blamed the YPG for a car bomb attack in Ankara last week that killed 29 people.
"Our allies must understand that they are at a crossroads... It is a fact that the [the Democratic Union Party] PYD and YPG are terrorist organizations that are extensions of the PKK," Erdogan said, Turkey-based newspaper Today Zaman reported.
"The PYD is supported because it fights against ISIL. Nusra Front is also fighting against ISIL. Why is it bad?" he asked, using another acronym for Daesh.
Erdogan also accused Russia of continuing to violate Turkish airspace, three months after Turkey shot down a Russian warplane near the Syrian border.