Turkish authorities have detained Istanbul Mayor Ekrem Imamoglu, a key rival to President Recep Tayyip Erdogan, as part of corruption and terror investigations, according to state broadcaster TRT, citing the Istanbul Prosecutor’s Office.

Ekrem Imamoglu was detained at his home on Wednesday, according to prosecutors, who said the charges against him were related to corruption and terrorism.

Prosecutors ordered that Ekrem Imamoglu and about 100 other people be detained, state-run media reported. Istanbul’s mayor is a high-profile member of the opposition.