He was arrested as part of an investigation into alleged corruption and terror links, media reported, a day after a university invalidated his diploma, effectively disqualifying him from running in the next presidential race.

Critics say the arrest of Istanbul's mayor is part of a mounting crackdown by Turkey's president to silence all dissent.

Turkish authorities have detained Istanbul Mayor Ekrem Imamoglu, a key rival to President Recep Tayyip Erdogan, as part of corruption and terror investigations, according to state broadcaster TRT, citing the Istanbul Prosecutor’s Office.