Istanbul mayor arrested ahead of selection to run against Erdogan

The main rival to Turkey's President Recep Tayyip Erdogan has been formally arrested and charged with corruption.

Ekrem Imamoglu, the mayor of the Turkish city of Istanbul, is expected to be selected as the opposition Republican People's Party's (CHP) 2028 presidential candidate in a ballot on Sunday.

He denies the allegations and says they are politically motivated. "I will never bow", he was quoted as saying after being remanded in custody pending trial.

His detention has sparked off some of the largest protests in more than a decade. Erdogan has condemned the demonstrations and accused the CHP of trying to "disturb the peace and polarise our people".

Imamoglu was one of more than 100 people, including other politicians, journalists and businessmen, detained as part of an investigation on Wednesday.

On Sunday, he was formally arrested and charged with "establishing and managing a criminal organisation, taking bribes, extortion, unlawfully recording personal data and rigging a tender".

Prosecutors want to charge him with "aiding an armed terrorist organisation", but the Turkish court said it was "not deemed necessary at this stage" to do so.

The CHP had a de facto alliance with the pro-Kurdish Peoples' Equality and Democracy Party (DEM) in connection with last year's local elections.

DEM has been accused of being affiliated with the PKK - or Kurdistan Workers' Party - which it denies. The PKK declared a ceasefire early this month, after waging an insurgency against Turkey for more than 40 years. It is proscribed as a terrorist group in Turkey, the EU, UK and US.

Imamoglu is seen as one of Erdogan's most formidable political rivals. He is the only person running in the CHP's presidential candidate selection.

The arrest does not prevent his candidacy and election as president. However, if he is convicted of any of the charges against him he would not be able to run.

A day before his arrest, Istanbul University announced it was revoking Imamoglu's degree due to alleged irregularities, a measure - which if upheld - would put his ability to run as president into doubt.

According to the Turkish constitution, presidents must have completed higher education to hold office.

Imamoglu's lawyers said they would appeal the decision to revoke his degree to the Constitutional Court and the European Court of Human Rights.

The Supreme Election Council will decide whether Imamoglu is qualified to be a candidate.

Erdogan has held office for the past 22 years, as both prime minister and president of Turkey. However, due to term limits, he cannot run for office again in 2028 unless he changes the constitution.

Opposition figures say the arrests are politically motivated. But the Ministry of Justice has criticised those who link Erdogan to the arrests, and insist on its judicial independence.