In a major blow to Turkish President Recep Tayyip Erdogan, the opposition Republican People's Party (CHP) candidate Ekrem Imamoglu has declared victory in the rerun of Istanbul's mayoral election, after initial results showed he was set for a clear win.
Imamoglu had won 54 percent of votes with almost all of the ballot boxes opened on Sunday, with the ruling Justice and Development Party's (AK Party) candidate trailing on 45 percent and conceding defeat.
Imamoglu promised a "new beginning" for Turkey's largest city and commercial hub.
"You have protected the reputation of democracy in Turkey," he told supporters.
His opponent, former Turkish Prime Minister Binali Yildirim, conceded defeat after initial results showed he was set to lose by a decisive margin.
"According to the result as of now, my competitor Ekrem Imamoglu is leading the race. I congratulate him and wish him good luck," Yildirim said.
CHP's projected win in the Istanbul election ends the 17-year rule by the AK Party in the metropolis.
The Istanbul mayoral election was first held on March 31, when Imamoglu secured 48.8 percent of the vote, while the AK Party's Yildirim held 48.55 percent, granting Imamoglu the title of mayor with a razor-thin margin.
The AK Party proceeded to file an "extraordinary objection" to the results, leading the Supreme Electoral Council (YSK) to annul the results and schedule Sunday's rerun.