ISTANBUL >> Hundreds of thousands of opposition supporters gathered outside Istanbul city hall Sunday night to protest the arrest of the city’s mayor, a key rival to Turkish President Recep Tayyip Erdogan.

Earlier Sunday, a court formally arrested Mayor Ekrem Imamoglu and ordered him jailed pending the outcome of a trial on corruption charges. His detention Wednesday morning sparked the largest wave of street demonstrations in Turkey in more than a decade, with large crowds gathering outside city hall for the fifth night in a row. It also deepened concerns over democracy and rule of law in Turkey.

His imprisonment is widely regarded as a political move to remove a major contender from the next presidential race, currently scheduled for 2028. Government officials reject the accusations and insist that Turkey’s courts operate independently.

“If you weren’t here today, if you hadn’t rushed here since the first day, if you had yielded to tear gas and barricades, if you had gotten scared and remained at home, then today a caretaker appointed by Tayyip Erdogan would be residing here in this building,” said Ozgur Ozel Sunday night, pointing at city hall as he spoke to the massive crowd chanting anti-government slogans. Ozel is the head of the Republican People’s Party, or CHP, to which Imamoglu belongs.

Suspicion of running criminal organization

The prosecutor’s office said the court decided to jail Imamoglu on suspicion of running a criminal organization, accepting bribes, extortion, illegally recording personal data and bid-rigging. A request for him to be imprisoned on terror-related charges was rejected although he still faces prosecution. Following the court’s ruling, Imamoglu was transferred to Silivri prison, west of Istanbul.

The Interior Ministry later announced that Imamoglu had been suspended from duty as a “temporary measure.” The municipality had previously appointed an acting mayor from its governing council.

Alongside Imamoglu, 47 other people were also jailed pending trial, including a key aide and two district mayors from Istanbul, one of whom was replaced with a government appointee. A further 44 suspects were released under judicial control.

Interior Minister Ali Yerlikaya said Sunday that 323 people were detained the previous evening over disturbances at protests.