Turkish police have detained more than 1,100 people, including journalists, during unrest after the arrest of Istanbul’s mayor, a minister said on Monday.

The demonstrations began in Istanbul after Ekrem Imamoglu, the main rival to Recep Tayyip Erdogan in the 2028 elections, was detained last week. They have since spread to more than 55 of Turkey’s 81 provinces, led to clashes with riot police and prompted international condemnation.

The popular 53-year-old Mr Imamoglu has been widely considered as the only politician who could defeat Turkey’s long-time leader Mr Erdogan at the ballot box.

In just four days he went from being the mayor of Istanbul – a post that started Mr Erdogan’s political rise decades earlier – to being arrested, interrogated, jailed and stripped of the mayorship as a result of a graft and terror probe.

On Sunday, he was voted in as the Republican People’s Party (CHP) candidate for the 2028 presidential run, with some 15 million people casting their ballots in a show of support for Mr Imamoglu.

Observers said it was the looming primary that triggered the move against Mr Imamoglu, the main political rival of Erdogan who has dominated Turkey’s politics since 2003, first as prime minister and then as president.

His arrest drew sharp condemnation from Germany, which called it “totally unacceptable” as Greece said moves to undermine civil liberties “cannot be tolerated”.

Overnight, France’s foreign ministry said it was a “serious attack on democracy”, and the EU warned Ankara it needed to demonstrate “a clear commitment to democratic norms”.