President Tayyip Erdogan led Turkey's runoff election with 54.78% support based on Sunday's initial results versus challenger Kemal Kilicdaroglu with 45.22%, with 67% of ballot boxes opened, according to data from the state-run Anadolu Agency.
The gap between the two candidates was expected to narrow as more and larger ballot boxes are tallied in cities. The Anadolu data was cited by several broadcasters.
Separate data published by the opposition ANKA news agency, and cited by Gazete Duvar, showed Kilicdaroglu leading with 50.95% versus Erdogan with 49.05%, with 67% of ballot boxes opened.
The presidential runoff could see Erdogan extend his rule into a third decade, pursuing Turkey's increasingly authoritarian trajectory, muscular foreign policy and unorthodox economic governance.
(Reporting by Ali Kucukgocmen and Ezgi Erkoyun; Editing by Jonathan Spicer and Giles Elgood)