Recep Tayyip Erdogan, Hassan Rouhani meet on sidelines of Syria summit in Russian resort city.
The bilateral meeting came before the start of a trilateral summit between the presidents of Turkey, Russia and Iran at the Rus Sanatorium in the coastal city of Sochi.
The meeting, which was closed to the media, started at 3.50 p.m. local time (1250GMT) and lasted for over 40 minutes.
During the trilateral meeting, Erdogan, Rouhani and Russia's Vladimir Putin will discuss progress made in the Astana peace talks as well as changes in de-escalation zones across Syria.
Following the meeting, the leaders will hold a joint news conference.
Later, Putin will host Erdogan and Rouhani at a dinner.
Turkey and Russia, together with Iran, are the guarantor countries that brokered a cease-fire in Syria in December 2016, leading to the Astana talks, which are running parallel to the Geneva talks for peace in Syria.