A buffer zone to be established in northern Syria cannot be subject to a Russian-Turkish agreement and should be decided with the Syrian government’s participation, Russian Foreign Minister Sergei Lavrov said on Friday, Anadolu Agency reported.

Turkey and the United States have been negotiating the establishment of a 20-mile safe zone in northern Syria to clear the area from the U.S.-backed Kurdish People’s Protection Units (YPG), which Turkey sees as an extension of the Kurdistan Workers Party (PKK), an armed group that has been fighting inside Turkey for more than three decades.

Turkish President Recep Tayyip Erdoğan met his Russian counterpart Vladimir Putin on Wednesday to discuss the situation in Syria. During two leaders’ joint press conference, Putin mentioned a 1998 agreement between Ankara and Damascus, which from 1984 to 2011 provided the expulsion of the terrorists of the PKK based in Syria.

"As for discussions about the buffer zone, the security zone, this cannot be the subject of an agreement between Russia and Turkey. This should be the subject of an agreement with the participation of the Syrian government, because ultimately the need to restore the Syrian government's control over the country's whole territory, including the zone, is clear to everyone,” Lavrov said on Friday at a press conference in Morocco. 

Russian minister said that both Moscow and Ankara had agreed on restoring Syria’s territorial integrity and sovereignty. 

The Russian diplomat also said that the Adana agreement could remove Turkey’s security concerns.

“Its essence consists in efforts to remove Turkey’s concern about its security, and the Syrian leadership decided to conclude this agreement, taking up certain commitments, and we believe that this agreement basically remains in effect and, as I understand, the signatory countries of this agreement are thinking in the same way,” Lavrov said.