Istanbul, 1 April 2024 (dpa/MIA) - Turkish President Recep Tayyip Erdogan's ruling AKP party has lost the mayoral election in Turkey's largest metropolis Istanbul, according to preliminary unofficial results.

Incumbent Ekrem Imamoglu from the main opposition CHP party has been re-elected, securing around 51% after almost all votes were counted, state news agency Anadolu reported.

Turkish President Recep Tayyip Erdoğan has expressed disappointment with the results, that showed a major setback for his ruling AKP party.

"Unfortunately, we were unable to achieve the result we desired and hoped for in the local election test," Erdoğan told supporters at his party headquarters in capital Ankara.

Main opposition CHP party secured the highest number of mayoral seats in 81 cities according to unofficial preliminary results shared by state news agency Anadolu.

Observers called the result a historic defeat for Erdogan's Islamic conservative party.

The secular CHP was able to defend the largest metropolis of Istanbul and the capital Ankara against the AKP with a large lead, Anadolu reported, citing 90% of the votes counted.

"We will honestly assess the results of the elections ... and courageously exercise self-criticism," Erdoğan told his supporters.

Ten months after his re-election as president, Sunday's poll was seen as a test of popularity for 70-year-old Erdogan and his party.

MIA file photo