Istanbul Mayor Ekrem Imamoglu appeared before police for questioning on terror-related charges on Saturday, a day after his interrogation over corruption allegations.

His arrest this week has sparked widespread protests across Turkiye, with demonstrators rallying in multiple cities to voice their opposition.

The mayor, who is a popular opposition figure and seen as a top challenger to President Recep Tayyip Erdogan, was detained on Wednesday following a dawn raid on his residence over allegations of financial crimes and links to Kurdish militants. Dozens of other prominent figures, including two district mayors, were also detained.

Many view the arrest as a politically driven attempt to remove a popular opposition figure and key challenger to Erdogan in the next presidential race, currently scheduled for 2028. Government officials reject accusations that legal actions against opposition figures are politically motivated and insist that Turkey’s courts operate independently.

On Friday, police questioned Imamoglu for four hours over the corruption accusations, during which he denied all of the charges, Cumhuriyet newspaper and other media reported. He was expected to be transferred to a courthouse later on Saturday for questioning by prosecutors and to face possible charges. His arrest has ignited protests that have steadily increased in intensity.

On Friday, police in Istanbul used pepper spray, tear gas and rubber bullets to push back hundreds of protesters who tried to break through a barricade in front of the city’s historic aqueduct while hurling flares, stones and other objects at officers.

Police also dispersed groups that had rallied outside of the city hall for a third night running, after the opposition Republican People’s Party leader, Ozgur Ozel, delivered a speech in support of the mayor.

Simultaneously, police broke up demonstrations in Ankara, the capital, as well as in the Aegean coastal city of Izmir, resorting to forceful measures at times, according to television images. Thousands marched in several other cities calling on the government to resign. A total of 97 people were detained nationwide in the protests, the Interior Ministry said. At least 16 police officers were injured.

Earlier, Erdogan said the government would not tolerate street protests and accused the opposition party of links to corruption and terror organisations. Authorities in Ankara and Izmir meanwhile, announced a five-day ban on demonstrations, following a similar measure imposed earlier in Istanbul. “An anti-corruption operation in Istanbul is being used as an excuse to stir unrest in our streets. I want it to be known that we will not allow a handful of opportunists to bring unrest to Turkiye just to protect their plundering schemes,” Erdogan said.

Imamoglu’s arrest came just days before he was expected to be nominated as the opposition Republican People’s Party’s presidential candidate in a primary on Sunday. Ozel has said that the primary, where around 1.5 million delegates can vote, will go ahead as planned.

The opposition party has also urged citizens to participate in a symbolic election on Sunday — through improvised ballot boxes to be set up across Turkiye — to show solidarity with Imamoglu.

In a message posted on his social media account Saturday, Imamoglu described his arrest as a “coup” and accused the government of exploiting the judiciary and worsening the country’s troubled economy.

“With your support, we will first defeat this coup, and then we will send packing those who caused this,” he wrote on the social media platform X.