It was a dramatic escalation in an ongoing government crackdown on the opposition and dissenting voices in Turkiye

The state-run Anadolu Agency said prosecutors issued detention warrants for the mayor, Ekrem Imamoglu, and some 100 other people. Among those detained was Imamoglu's close aide, Murat Ongun

Authorities also closed several roads around Istanbul and banned demonstrations in the city for four days in an apparent effort to prevent protests following the arrest

Critics say the crackdown follows significant losses by Erdogan's ruling party in local elections last year amid growing calls for early national elections. Government officials insist that the courts operate independently and reject claims that legal actions against opposition figures are politically motivated

The arrest came during a search of Imamoglu's home, but it was not immediately clear if police confiscated anything at the site

The mayor's wife, Dilek Imamoglu, told the private Now television station that police arrived at their residence before dawn and that the mayor was taken at around 7:30 am

The Istanbul Stock Exchange's main index dropped by 7 per cent over news of the mayor's arrest, triggering a temporary halt to trading to prevent panic selling and stabilize the market

A day earlier, a university in Istanbul invalidated Imamoglu's diploma, effectively disqualifying the popular opposition figure from running in the next presidential race. Having a university degree is a requisite for running in elections under Turkish law

The mayor's party, the main opposition Republican People's Party, or CHP, was to hold a primary on Sunday where Imamoglu was expected to be chosen for its candidate in future presidential elections