Foreign Minister Mevlüt Çavuşoğlu said the PKK's Syrian affiliate the Democratic Union Party (PYD) and its armed wing, the People's Protection Units (YPG), will not be at the negotiating table at the Syria National Dialogue Congress, which is planned to be held in the Russian city of Sochi on Jan. 29-30.

"The YPG won't be at the table in Sochi. Is PKK representative of Turkish Kurds? Can a terrorist group be representative of the Kurdish people. We will explain this to the world. There are many Kurdish groups that do not embrace the YPG's ideas," the foreign minister said in a televised interview.

He added that discussions with Russia on the imminent operation in Afrin and the usage of Syrian airspace are ongoing. "The operation should be conducted in cooperation. Russian observers in Afrin should not be affected by the offensive. Even though we have divergence on several issues, the two countries are working together," he said.

Çavuşoğlu also said Turkey has always been defending the territorial integrity of Syria, and Turkey's opinion on Bashar Assad's future has not changed.

Turkey, Russia and Iran are the guarantor countries that brokered a cease-fire in Syria in December 2016, at the Astana talks, which ran parallel to the U.N.-backed discussions in Geneva to find a political solution to the six-year war. They also agreed on the convention of the Sochi congress, which is expected to be participated by all segments of Syrian society except for terrorist groups.