ISTANBUL (AP) — Protests erupted across multiple Turkish cities on Friday as people rallied against the arrest of Istanbul’s mayor and top rival to President Recep Tayyip Erdogan, despite the Turkish leader’s stern warning that street protests would not be tolerated.

In Istanbul, police 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 and threw flares, stones and other objects at them.

Police also 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 images shown on the private Halk TV. Thousands marched in several other cities calling on the government to resign, the station reported.

At least 97 people were detained nationwide during the protests, Interior Minister Ali Yerlikaya said.

Mayor Ekrem Imamoglu was arrested in a dawn raid on his residence on Wednesday over alleged corruption and terror links, escalating a crackdown on opposition figures and dissenting voices. Several 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.

Imamoglu was questioned by police for four hours over corruption accusations, during which he denied all the charges, the Cumhuriyet newspaper and other media reported. He was expected to be transferred to a courthouse Saturday evening for questioning by prosecutors.

His arrest has sparked the largest protests since 2013, when Turkey was rocked by mass anti-government demonstrations that left eight people dead.

Earlier on Friday, the leader of Turkey’s main opposition party, Ozgur Ozel, renewed a call on supporters to take to the streets for peaceful demonstrations, while authorities widened a ban on protests and criticized the appeal 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.

Addressing a large rally outside the city hall, Ozel accused Erdogan of using the judiciary as tool after failing to defeat the mayor “in a fair way.”

Erdogan, increasingly authoritarian after more than two decades in office, said the government would not tolerate street protests and accused the opposition party of links to corruption and terror organizations.

“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,” Erdogan said. “Just as we have not surrendered to street terrorism until now, we will not bow to vandalism in the future either.”

On Friday, authorities in Ankara and Izmir announced a five-day ban on demonstrations, following a similar measure imposed earlier in Istanbul. Authorities on Friday announced more road closures in Istanbul and shuttered metro stops near a university in Ankara, where violent clashes occurred a day earlier.

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 Turkey — to show solidarity with Imamoglu.

Analysts say Imamoglu could be removed from office and replaced by a “trustee mayor,” if he is formally charged with links to the outlawed Kurdistan Workers’ Party, or PKK, which is listed as a terrorist organization by Turkey and its Western allies.

Meanwhile, Ozel also said the opposition party would hold an extraordinary party congress on April 6, to thwart any attempts by the authorities to appoint a “trustee chairman” to lead the party. The decision came amid speculation that authorities could annul the party’s last congress, held in 2023, over alleged vote-buying and other irregularities, and appoint a handpicked leader.

Also Friday, gunmen opened fire on the Iraqi consulate in Istanbul, the Turkish and Iraqi foreign ministries said. No injuries were reported.

Iraq’s foreign ministry said in a statement that unknown assailants riding on a motorcycle and armed with an assault rifle, fired eight shots at the building before fleeing.

The Turkish foreign ministry said in a statement that “the necessary investigation is being carried out meticulously by our security units” and “those responsible will be brought to justice.” It said that measures had been taken to secure Iraqi diplomatic missions in Ankara, Istanbul and Gaziantep.

It was not clear what may have motivated the shooting.