Turkey headed for a runoff presidential vote after President Recep Tayyip Erdogan outperformed projections in Sunday's election as he sought to extend his two-decade rule, holding a sizable lead over his rival but falling short of an outright majority.

Neither Erdogan nor rival Kemal Kilicdaroglu cleared the 50% threshold needed to avoid a second round, to be held on May 28, in an election seen as a verdict on Erdogan's increasingly authoritarian path.

The presidential vote will decide not only who leads Turkey, a NATO-member country of 85 million, but also whether it reverts to a more secular, democratic path; how it will handle its severe cost of living crisis and manage key relations with Russia, the Middle East and the West.