(March 23): A Turkish court on Sunday formally arrested President Recep Tayyip Erdogan’s top political rival, in a decision likely to stoke further protests and keep local markets under pressure as tensions mount.

Ekrem Imamoglu, the mayor of Istanbul from the main opposition Republican People’s Party, or CHP, was formally arrested on corruption, NTV news channel said. Imamoglu, who will be jailed pending trial, is also facing terrorism-related charges. The decision for that has yet to be announced. He’s denied all charges.

The mayor, who runs a city of over 15 million people, had been preparing to announce his candidacy for a presidential election due by 2028 on Sunday.

Imamoglu was taken into police custody on Wednesday, with the opposition denouncing the move as politically motivated. He appeared before a judge on early Sunday, along with dozens of others.

His detention sparked a wave of anti-government protests, with hundreds of thousands defying a ban in place since Wednesday. Tensions translated into financial markets in the past week, with Turkish stocks slumping and an emergency interest-rate increase failing to halt a selloff in the lira.

Erdogan’s aides have touted him to run for a third term term as president, extending more than two decades in power — first as prime minister, then president. Imamoglu is seen as a formidable challenger to Erdogan if he were to run, having previously defeated the president’s handpicked candidate in two local elections.

Should he want to prolong his tenure, Erdogan will need to broaden his support base in parliament for it to call for a snap election or change the constitution.

The mayor’s arrest comes amid a wave of detentions and investigations since the turn of the year, on charges including “insulting the president” and involvement in a decade old anti-government protest.

Erdogan warned the main opposition party on Friday that he won’t submit to “street terror,” referring to a call for nationwide protests over Imamoglu’s detention. The CHP party is “rapidly losing its status as a legitimate political party,” he said.

Uploaded by Magessan Varatharaja