Tens of thousands of Turks flooded streets across the country Sunday night following the arrest of Istanbul Mayor Ekrem Imamoglu.

The popular opposition figure had been set to become the Republican People’s Party’s (CHP) presidential nominee for 2028 before authorities remanded him to custody on Wednesday on charges of bribery, extortion, and “establishing a criminal organization.”

“I will never bow,” Imamoglu declared on social media before being transported to Silivri prison. He called the case “a black stain on our democracy” and maintained the charges are politically motivated.

The arrest triggered immediate backlash, with demonstrations erupting in 55 of Turkey’s 81 provinces. In Istanbul, protesters waving Turkish flags faced off against riot police who deployed water cannons, tear gas, and pepper spray to disperse crowds.

President Recep Tayyip Erdogan condemned the unrest, accusing opposition parties of attempting to “disturb the peace and polarize our people.” More than 700 protesters have been arrested since Imamoglu was detained, along with over 100 opposition politicians, journalists, and businessmen, according to the BBC.

Political analysts consider Imamoglu the strongest threat to Erdogan’s political dynasty, which has dominated Turkey for over two decades. Erdogan himself faces constitutional term limits barring another run in 2028, unless he decides to rewrite the country’s constitution, something he’s done before.

In 2017, Erdogan pushed through a controversial referendum that transformed Turkey from a parliamentary system to a presidential one, abolishing the prime minister position and significantly expanding his powers with just 51.4% voter approval.

Despite being jailed and stripped of his mayorship, CHP still nominated Imamoglu as their candidate with some 1.6 million votes coming in support. Though the 53-year-old can legally maintain his candidacy while awaiting trial, any conviction would disqualify him from the 2028 presidential race.

Furthermore, prior to his arrest, Istanbul University announced it was revoking Imamoglu’s degree citing “irregularities.” If upheld, it would disqualify him from seeking the presidency, as Turkish law requires candidates to have completed higher education.