Turkish authorities have detained three more mayors from the main opposition Republican People's Party, Reuters reported.
The Istanbul Chief Prosecutor's Office said the mayors of the cities of Adana and Adiyaman were detained on extortion charges, along with eight others.
The mayor of Antalya and the deputy mayor of Istanbul's Buyukcekmece district were also detained.
In March, Istanbul Mayor Ekrem Imamoglu, President Recep Tayyip Erdogan's main political rival, was arrested on corruption charges he denies.