For the third day in a row, tens of thousands of people gathered outside Istanbul's city hall on Friday to protest the arrest of the city's mayor, who is a key opponent of President Recep Tayyip Erdogan. This happened despite Erdogan's warning that street protests would not be allowed.

The demonstration remained peaceful, but about 500 meters away, some protesters clashed with the police. Officers used pepper spray and tear gas to stop a group that tried to break through a barricade near the historic aqueduct. Some protesters threw flares and other objects at the police. Police used water cannons to disperse protests in Turkey’s capital, Ankara and the coastal city of Izmir. On Wednesday morning, authorities arrested Mayor Ekrem Imamoglu at his home in a dawn raid, accusing him of corruption and ties to terrorism. The crackdown also led to the detention of several other key figures, including two district mayors. Many believe that the arrest was a politically motivated attempt to remove a popular opposition figure and a key contender to Erdogan in the next presidential election, which is presently slated for 2028. Government officials deny that legal measures against opposition figures are politically motivated, insisting that Turkey's courts are autonomous. According to Cumhuriyet newspaper and other media, Imamoglu was questioned by the police for four hours regarding corruption accusations. He denied all the charges. He is expected to be taken to a courthouse on Saturday evening for further questioning by prosecutors. 

The arrest has led to Turkey's biggest protests since 2013 when mass anti-government demonstrations resulted in eight deaths. On Friday, Ozgur Ozel, the leader of Turkey's main opposition party, urged people to join peaceful protests. Meanwhile, authorities expanded a ban on demonstrations and criticised his call as irresponsible. “I invite tens of thousands, hundreds of thousands, and millions, to peacefully demonstrate, express our democratic reaction, and exercise our constitutional rights,” he said. Speaking at the rally, he accused President Erdogan of misusing the judiciary because he couldn’t defeat the mayor fairly.  Erdogan, who has become more authoritarian after ruling for over 20 years, said the government would not allow street protests. He also accused the opposition party of being connected to corruption and terrorist groups. “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 Turkey just to protect their plundering schemes,” Erdogan said. “Pointing to the streets instead of courtrooms to defend theft, plunder, lawlessness and fraud is a grave irresponsibility. Just as we have not surrendered to street terrorism until now, we will not bow to vandalism in the future either, he added. 

The most intense clash took place on Thursday night at Ankara's Middle East Technical University. Police used tear gas and water cannons to break up the protest. Students claimed that rubber bullets were also used, but the government denied this. According to the Interior Ministry, over 50 people were arrested, and 16 police officers were injured. On Friday, officials in Ankara and Izmir banned protests for five days, just like Istanbul had done earlier. Authorities also announced more road closures in Istanbul and shut down metro stations near the university in Ankara. İmamoğlu was arrested just days before he was expected to be nominated as the presidential candidate for the opposition Republican People's Party (CHP) in a primary on Sunday. Özel has confirmed that the primary, where about 1.5 million delegates can vote, will still take place as planned. The opposition party has called on citizens to take part in a symbolic election on Sunday using makeshift ballot boxes set up across Turkey to show support for Imamoglu. Experts believe that if Imamoglu is officially accused of having ties to the banned Kurdistan Workers' Party (PKK), which is considered a terrorist group by Turkey and its Western allies, he could be removed from office and replaced by a trustee mayor.

Ozel also announced that the opposition party will hold a special party congress on April 6 to prevent authorities from appointing a trustee as the party's leader. This decision comes amid speculation that the authorities might cancel the party's last congress, held in 2023, due to allegations of vote-buying and other irregularities, and replace the leader with their own choice. Meanwhile, on Friday, the Borsa Istanbul stock market index dropped by about 7%, leading to temporary trading suspensions to stop panic-driven selling.