The arrested Istanbul mayor Ekrem Imamoglu is expected to appear in court tonight, BNR reported.
A decision will then be made on his release or detention until the start of the trial.
Earlier, Imamoglu rejected the terrorism charges brought against him, according to a court document seen by Reuters, after he was detained by Turkey on Wednesday for alleged corruption and terrorism.
The Istanbul mayor was expected to be officially nominated as a candidate for the country's president for the 2028 elections tomorrow.
Turkish authorities announced that they had detained 343 people at the thousands of protests against the arrest of Istanbul mayor Ekrem Imamoglu, which took place last night in several cities, including Istanbul and the capital Ankara.
According to opposition figures, hundreds of thousands of people took part in the protests last night, ignoring President Recep Tayyip Erdogan's warning that he would not tolerate "street terrorism".
In Istanbul, Ankara and Izmir, clashes broke out with police, who used tear gas, rubber bullets and water cannons to disperse the protesters. Media reports said dozens of homes were searched overnight.