Erdogan's opponent Kilicdaroglu holds final rally

STORY: Making a heart sign with his hands, which has become an emblem of his campaign, Kilicdaroglu urged the huge crowds attending the rally to vote, amid concerns of electoral malpractice, assuring them that his party, the CHP, had been working on what he called "ballot box security".

Kilicdaroglu has a narrow lead over Erdogan in the polls. If no candidate secures more than half of the votes in the first round, then a May 28 run-off will be held between the two leading candidates.

Erdogan's Islamist-rooted AK Party counts the nationalist MHP as its main ally, while the secularist CHP and five other parties form an opposition alliance that is expected to get support from the main Kurdish party HDP, giving it an edge in some polls.