Istanbul Mayor Ekrem Imamoglu has denied corruption charges brought against him, according to a court document seen by Reuters on Friday, after he was detained on Wednesday for alleged corruption and terrorism charges.

Turkish authorities detained President Tayyip Erdogan's main political rival on Wednesday on charges including corruption and aiding a terrorist group, in what the main opposition party called "a coup attempt against our next president.

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

As Turkey’s opposition parties rally in solidarity with Istanbul's mayor, Turkish authorities have moved forward with more detentions.

The leader of Turkey’s main opposition on Friday renewed a call for supporters to take to the streets for peaceful demonstrations against the arrest of Istanbul’s mayor and top rival to President Recep Tayyip Erdogan. It came as authorities widened a ban on protests and criticised the appeal as irresponsible.