President Erdogan fails to regain Turkey's big cities that he lost five years ago.
Turkey's main opposition party has claimed big election victories in the main cities of Istanbul and Ankara.
The results are a significant blow for Recep Tayyip Erdogan, who had hoped to regain control of the cities less than a year after he claimed a third term as president.
But Ekrem Imamoglu, who first won the city in 2019, scored a second victory for the secular opposition CHP.
Mr Erdogan had vowed a new era in Turkey's megacity of almost 16 million people, but the incumbent mayor of Istanbul was on course to win more than 50% of the vote, over 11 points ahead of the president's AK Party candidate.
This was also the first time since Mr Erdogan came to power 21 years ago that his party was defeated across the country at the ballot box.