Turkish police have detained the strongest rival to President Recep Tayyip Erdogan, a move that experts say is aimed at removing all possible contenders ahead of the next presidential election and further stretching his rule.

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 against our next president".

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.