Never be sad, never be despondent, never lose hope, Istanbul Mayor Ekrem Imamoglu said Sunday, addressing his supporters as he faces an arrest and possible criminal charges over alleged corruption. 

"Never be sad, never be despondent, never lose hope. We will... remove this black stain on our democracy with our own hands. The day will come when people in charge of this process will answer before the Almighty, both in this world and the next. I stand tall, I will never be broken. Everything will be great," Imamoglu wrote on X, addressing his supporters on Sunday.

Imamoglu, the main opposition Republican People's Party (CHP)'s sole presidential candidate, was taken into custody earlier this week on corruption charges. His message comes amid rising political tensions and protests across Istanbul, where demonstrators have defied bans on public gatherings to condemn what many see as politically motivated charges.

On the same day as Imamoglu's address, Turkish media reported new legal developments. Sozcu TV confirmed that a court had issued a formal arrest warrant for Imamoglu, while Star newspaper reported that a separate request for his arrest in a terrorism investigation was rejected. According to Halk TV, the mayor plans to challenge the decision, with the final ruling expected from the Constitutional Court.

The corruption probe has widened to include more than 90 individuals, among them several senior officials from the Istanbul municipality who were also detained. Imamoglu was first taken into custody on Wednesday.

Read more: Istanbul mayor Imamoglu denies terror, corruption allegations

Despite the arrest, the CHP went ahead with its primaries on Sunday to select a candidate for a likely snap presidential election, reaffirming Imamoglu's position as their nominee.

"I do not intend to give in," Imamoglu stated, rejecting what he views as an attempt to pressure him out of the race.

The government's critics argue that the arrest is part of a broader effort to sideline President Recep Tayyip Erdogan's most serious challengers ahead of the 2028 election. Imamoglu's popularity, especially in Turkey's largest city, has positioned him as a potential threat to Erdogan's hold on power, making the legal actions against him all the more contentious.