Miksic's assistants showed reporters two ballots on which Miksic's name was circled but which were found outside of sealed boxes with the ballots.
Miksic said that he would hold a rally in Zagreb's central square on Friday to thank all who supported him during his presidential campaign.
He added that he still had not decided about the future course of his political career or his participation in the upcoming local elections.
Asked to comment on an article in the latest issue of Nacional weekly, which says that Miksic has embellished his biography for election purposes and deceived his business partners, Miksic said: "It is well known who owns Nacional, because it very often advocates the positions of Stjepan Mesic".