Istanbul Mayor Ekrem Imamoglu was officially placed under custody by a Turkish court for trial on corruption charges, just days after his detention sparked nationwide protests, Aljazeera reported.

Imamoglu and at least 20 other people were imprisoned as part of a corruption investigation, the court said. A decision on a separate probe into terror has not yet been made.

The court opted to release the mayor under judicial control measures for a second terror-related charge, according to stations Halk TV and AHaber, potentially preventing the government from choosing a trustee to oversee the country's largest city, according to Aljazeera

The mayor, a key opposition member and prospective contender to Turkish President Recep Tayyip Erdogan, was jailed by the government on Wednesday on charges of "terrorism" and corruption.

Imamoglu has refuted all claims, referring to them as part of a "smear campaign".