A top Syrian Kurdish official accused Turkey on Tuesday of settling Turkmen and Arab families in villages seized in the Turkish army's campaign in the Kurdish Afrin region.
A senior Turkish official said the accusation was "absolutely false".
Turkey launched a major offensive in the northwestern Syrian region in January, aiming to drive out the Kurdish YPG militia.
Redur Xelil, the head of foreign relations in the Syrian Democratic Forces (SDF), a YPG-dominated militia alliance, said Turkey was conducting a policy of "demographic change" in the area.
"The Turkish government is settling Turkmen and Arab families in the villages of Afrin that it occupied after forcing out its people and is distributing the belongings of the people of Afrin to the new settlers," he said in a written message to Reuters.
The senior Turkish official said: "The claim that Arabs and Turkmen are being placed in Afrin is absolutely false ... A transfer of population to that region to change the demographic structure is out of the question."
Turkey views the YPG as an extension of the Kurdistan Workers' Party (PKK), which has waged a three-decade insurgency in Turkey and is listed as a terrorist group by the United States, the European Union and Turkey.
The United States regards the YPG as a valuable partner in the fight against Islamic State (IS) militants in northern Syria.
Xelil added that Turkey's role in northern Syria was "laying the ground for ethnic conflicts and strife between Arabs, Kurds and Turkmen".