Turkish authorities detained Ekrem Imamoglu, President Recep Tayyip Erdogan’s most prominent rival, in a widening crackdown on opposition that triggered a selloff in Turkish markets.

The lira sank to a record low before clawing back some of its losses - it now trades down 6% at 40 per dollar. Turkey’s main stock index slumped 6.9% in early trading in Istanbul, while the government’s 10-year lira bond yields soared nearly 200 basis points to 30.11%.

The detention comes a day after Turkish authorities revoked the university diploma of Imamoglu, a move that could bar him from challenging Erdogan in the next presidential election. A higher education degree is a mandatory requirement to run for the presidency.

The 54-year-old Istanbul mayor, one of Turkey’s most popular politicians, is widely seen as a top contender for the presidency. He beat Erdogan’s handpicked candidate in last year’s Istanbul mayoral race and was set on Sunday to be named the presidential candidate for the Republican People’s Party, the main opposition group known as the CHP.

Imamoglu was taken into custody early Wednesday morning at his home. He is among more than 100 individuals detained in an investigation into alleged fraud, bribery, and running a criminal organization, according to a statement from Istanbul prosecutor’s office. The detained include two district mayors from Istanbul, both from Imamoglu’s party.

In a voice message shared by his team, Imamoglu denounced his arrest, accusing authorities of weaponizing the police. His party has called the charges baseless and politically motivated.

The Istanbul governor’s office has imposed a four-day ban on demonstrations and protests, while also closing multiple streets around the police station where Imamoglu is likely to be taken. The restrictions cast doubt on whether the opposition’s planned rally on Saturday — where Imamoglu was expected to solidify his bid for the presidency — will be allowed to proceed.

Some social media platforms and messaging apps, including X, WhatsApp, and TikTok, were briefly restricted in Turkey, according to NTV.

Erdogan’s tightening grip

Imamoglu’s detention follows years of legal battles against him. He already faces multiple lawsuits, the most serious of which could lead to a prison sentence of more than seven years and a ban from holding public office. His 2019 victory in Istanbul — a city of more than 15 million people that Erdogan once governed — was a major blow to the president’s ruling AK Party.

The next presidential election is officially set for 2028, but Erdogan needs an early vote if he wants to run again for presidency, according to Turkish constitution.

The moves are part of a broader pressure campaign against opposition figures, activists, and critical voices. Imamoglu’s detention follows the arrest in January of Umit Ozdag, the leader of a small nationalist party and a vocal critic of Erdogan. Investigations have also ensnared national politicians, journalists, and even a celebrity agent earlier this year. Former Kurdish leader Selahattin Demirtas has been imprisoned for years.

Imamoglu’s detention — along with the arrest of dozens of others and new protest bans — signals a deepening political crisis in the country. It comes with Erdogan having steadily consolidated power over the judiciary, media, and security forces.

Imamoglu’s re-election as mayor last year — against a backdrop of high inflation — was part of a national swing away from Erdogan and the AK Party toward the CHP, which now holds power in most of Turkey’s largest cities.

The mayor was already waiting for an appeal court decision after being handed a two-year prison sentence for insulting public officials in 2019.

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