Istanbul mayor and Erdogan rival arrested in major crackdown

Turkish authorities have detained the mayor of Istanbul, just days before he was due to be selected as a presidential candidate.

Ekrem Imamoglu, from the secular Republican People's Party (CHP), is seen as one of Turkish President Recep Tayip Erdogan's strongest political rivals.

Prosecutors accused him of corruption and aiding a terrorist group, calling him a "criminal organisation leader suspect".