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

The arrest of Istanbul’s mayor, a popular opposition leader, marks a dramatic escalation in an ongoing government crackdown on dissenting voices in Turkey.

Ekrem Imamoglu, the mayor of Istanbul and a popular figure, had boasted jokingly that he was the only person to have beaten Recep Tayyip Erdogan’s ruling party in three local elections