The two leaders also discussed bilateral ties, the source, who asked not to be named due to restrictions on talking to the media, said.
“National Dialogue Congress in Sochi would be complementary, not an alternative to Geneva,” Erdogan said.
The Turkish president also underlined that the congress would not include terrorist organizations.
The present process aims to organize free and fair elections for all Syrians under the auspices of the United Nations, he added.
Last Wednesday, Erdogan met Russian President Vladimir Putin and Iranian leader Hassan Rouhani in the Black Sea resort city of Sochi to discuss Syria.
During the meeting, the three leaders agreed to convene a congress of Syrian groups to advance a political solution for the war-torn nation.