• Istanbul Mayor Ekrem Imamoglu of the main opposition Republican People's Party (CHP) gestures as he addresses supporters during an election rally ahead of the May 28 presidential runoff vote, in Istanbul on May 27, 2023. (AFP) 

Turkish police have detained Istanbul Mayor Ekrem Imamoglu on charges of leading a criminal organization, bribery, tender rigging, and aiding a terrorist group, broadcaster CNN Turk reported on Wednesday.

Following Imamoglu’s detention, Turkiye restricted access to multiple social media platforms, including X, YouTube, Instagram, and TikTok, according to the NetBlocks internet observatory.

In a separate development, a Turkish university on Tuesday revoked Imamoglu’s degree, alleging it was fraudulently obtained.

The decision deals a significant blow to the mayor—widely regarded as President Recep Tayyip Erdogan’s most formidable political rival—just days before he was set to be officially named the main opposition CHP party’s presidential candidate for the 2028 election.

Under the Turkish constitution, a presidential candidate must hold a higher education degree.

Imamoglu denounced the ruling as "unlawful" and vowed to challenge it in court.

"We will fight this illegitimate decision in court," said the 53-year-old, who has faced mounting legal challenges that critics describe as politically motivated.

"We will build a system that will erase injustice from this country's memory," he added, warning that those responsible for the decision would one day be held accountable.

Erdogan has long denied allegations that he himself never completed university and was therefore constitutionally ineligible for the presidency.

In a statement on X, Istanbul University announced that the degrees of 28 individuals, including Imamoglu, would be "withdrawn and cancelled on the grounds of... obvious error" but did not provide further details.

Opposition CHP leader Ozgur Ozel condemned the move as a "black mark" on Turkiye’s legal and academic institutions, insisting it would not deter the party from nominating Imamoglu as its presidential candidate. He is expected to be formally named at a party congress on Sunday.

"The action taken is not legal, but political... we stand behind Ekrem Imamoglu... (who) is our presidential candidate", Ozel declared, expressing hope that the courts would overturn the decision swiftly.

CHP lawmaker Murat Emir also denounced the ruling as "a heavy blow to our democracy."

On its part, Human Rights Watch called for the immediate release of the Turkish mayor, calling his arrest and charges against him "politically motivated" and "bogus".

Imamoglu’s office had previously published a copy of his business management diploma, issued by Istanbul University in 1995, following claims by a journalist that he did not hold a degree.

In recent years, the mayor has been targeted by multiple legal investigations, with three new cases opened against him this year alone.

In 2022, he was sentenced to two years and seven months in prison and barred from political activity for "insulting" election officials in Istanbul. He has appealed the verdict, with the case still pending.

A vocal critic of Erdogan—who himself rose to the presidency after serving as Istanbul’s mayor—Imamoglu has denounced the legal proceedings against him as judicial "harassment."

Istanbul University stated that it had submitted related documents to the Istanbul prosecutor’s office and the Higher Education Council.

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