The announcement was made by the head of the party's parliamentary group, at a press conference in Istanbul.
The candidate of the Republican People, Ekrem İmamoğlu, and the winner of the Istanbul Municipality in the elections of local administrations in Turkey last March, arrived at the Palace of Justice, to receive the document of the mayor of the election commission in the city.
The arrival of Ekrem İmamoğlu coincided with the Palace of Justice as a number of party supporters rallied in front of the palace.
The vote count in local elections in Istanbul ended on Wednesday, and he said he expected to be as mayor despite Erdogan's party's call for a re-election in Turkey's largest city.
Preliminary results of the March 31 vote showed that the opposition Republican People's Party (CHP) won the municipal elections by a narrow margin in Istanbul, ending 25 years of control by the AK Party and its predecessors over the city.
The defeat is a tough blow for Erdogan, who began his political career as mayor of Istanbul in the 1990s.
The source: Agencies