Izmir Mayor Cemil Tugay is expected to join the ruling Justice and Development Party (AK Party) in the coming days after meeting President Recep Tayyip Erdogan in Ankara last week.
According to an Izmir municipality source speaking to Türkiye Today, the transition is highly likely to be finalized, with an official announcement expected this week.
"There is still no official confirmation on that switch; however, it is highly likely that he will announce the shift this week," the source said.
Turkish media have recently reported heavily on rumors of Tugay's impending defection. The Izmir mayor had previously denied the rumors in a public statement.
Tugay had resigned from the Republican People's Party (CHP) in June, citing a wave of expulsions and what he called an unacceptable erosion of the party's democratic will.
The resignations marked the end of an unbroken 23-year CHP hold on Izmir, a western coastal city long regarded as the party's most reliable urban stronghold.
Cemil Tugay's switch to the AK Party will mark the first time in history that the AK Party rules historically secular Izmir, Türkiye's third-biggest city.
Since its rise to power in 2002, the AK Party has dominated the majority of metropolises like Istanbul, Ankara and Bursa for years. However, the mayor's office in Türkiye's third-largest city has consistently eluded the ruling party.
Izmir has long been recognized as the undisputed bastion of Türkiye's secular and Western-oriented electorate. The city's social fabric and dominant political culture have historically served as a fortress for the opposition.
The city has been one of the main centers of anti-government protests in the last two decades.