President Recep Tayyip Erdoğan held separate meetings Saturday with German, Russian and French leaders ahead of a four-way Syria summit to be held in Istanbul.
Erdoğan's closed-door meetings with Angela Merkel, Vladimir Putin and Emmanuel Macron took place at the Vahdettin Pavilion in Istanbul's Üsküdar district.
No further details of the gatherings were provided.
The four-way summit on Syria between Turkey, Russia, Germany and France is set to kick off later Saturday.
Staffan de Mistura, the UN special Syria envoy, will also be present.
During the summit, the participants will comprehensively discuss the Syrian conflict, focusing on the situation on the ground, the political process, and ways to harmonize joint efforts to find a lasting solution.
The leaders will also discuss the Sept. 17 agreement between Ankara and Moscow to establish a demilitarized zone in Syria's northwestern province of Idlib.
Under the deal, opposition groups in Idlib are to remain in areas where they are already present, while Russia and Turkey carry out joint patrols in the area to prevent renewed fighting.
On Oct. 10, the Turkish Defense Ministry announced that the Syrian opposition and other anti-regime groups had completed the withdrawal of heavy weapons from the Idlib demilitarized zone.
Syria has only just begun to emerge from a devastating conflict that began in 2011, when the Assad regime cracked down on demonstrators with unexpected ferocity.
