The UK-based Syrian Observatory for Human Rights says the handover was arranged by Russia. The Turkish-backed Free Syrian Army (FSA) members were killed during clashes between US-backed FSA on Monday.
A YPG officer said on Tuesday that it will hand over the bodies of nine FSA fighters to Turkey, following clashes with the Turkish-backed Free Syrian Army (FSA).
Barousek Hasakeh, an officer in the US-backed Syrian Defence Force (SDF), says nine were killed in clashes on Monday in Ain Daqna, a small village on the front lines between the rival forces, both of which are also battling Daesh.
Hasakeh did not identify the nationalities of the fighters.
The UK-based Syrian Observatory for Human Rights says the handover was arranged by Russia. The Russian military maintains a handful of posts in northern Syria.
Hasakeh said clashes with the Syrian opposition forces died down on Tuesday, but shelling continued throughout the day.
The YPG are a key component of the US-backed SDF, but are considered by Turkey to be the Syrian branch of PKK, which is listed as a terrorist organisation by the US, EU and Turkey.
Ankara resolved at National Security Council meeting earlier that Turkey will not accept PKK/YPG presence in Syria even if they are battling Daesh.
Regime claims sanctions are "unjustified"
Also on Tuesday, the Syrian regime blasted the European Union for imposing new sanctions on 16 Syrian military and scientific officials it suspects are involved in chemical weapons attacks against civilians.
Syria's news agency quoted an unnamed Foreign Ministry official as saying that the sanctions are "unjustified" and aim to mislead international public opinion.
It said Damascus has had no chemical weapons since it joined the international chemical weapons convention four years ago.
In May, the EU extended restrictive measures against Syria by a year. The 28-nation EU had previously imposed travel bans and frozen the assets of 240 people and 67 organisations in Syria.