Il Nuovo Postiglione - Turkey braces for fourth night of protest as mayor arrives in court

As the crowds began massing outside Istanbul City Hall, a convoy carrying the 53-year-old mayor arrived at Caglayan court on the other side of the city, a spokesman for his administration said.

Outside the court, police had set up a tight security cordon with nearly 20 anti-riot vehicles on standby, while some 500 protesters stood nearby, chanting: "Shoulder to shoulder against fascism!" an AFP correspondent said.

Inside, Imamoglu -- the chief rival of President Recep Tayyip Erdogan -- was to be questioned by prosecutors in two investigations, one alleging graft and a second for allegedly "helping a terrorist organisation".

He was arrested on Wednesday, just days before he was to be formally named the main opposition CHP's candidate for the 2028 presidential race.

"We are here today to stand up for the candidate we voted for," 30-year-old Aykut Cenk told AFP outside the court, holding a Turkish flag.

"Just as people took the streets to stand up for Erdogan after the July 15 (2016) coup, we are now taking to the streets for Imamoglu," Cenk said.

"We are not the enemy of the state, but what is happening is unlawful."

- Journalists 'targeted' -

The demonstrations began on Wednesday in Istanbul and have since spread to at least 55 of Turkey's 81 provinces, with Diyarbakir, the main city in the Kurdish-majority southeast, saying it would also participate on Saturday.

Since Thursday, riot police have clashed repeatedly with the protesters, deploying tear gas, rubber bullets and water cannon against them in Istanbul, the capital Ankara and the western coastal city of Izmir.

The unrest has spread rapidly despite a protest ban in Turkey's three largest cities and a warning from Erdogan that the authorities would not tolerate "street terror".

Police had arrested 343 protesters, Interior Minister Ali Yerlikaya said.

Turkey's Journalists Union on Saturday said the police had "deliberately targeted" journalists, saying many had been "severely beaten, shot with rubber bullets and had equipment broken".

"We condemn the heavy-handed and completely arbitrary riot police violence against journalists," said Erol Onderoglu of Reporters Without Borders (RSF), demanding Yerlikaya "ensure those responsible be severely punished".

Already named in a growing list of legal probes, Imamoglu -- who was resoundingly re-elected last year -- has been accused of "aiding and abetting a terrorist organisation", namely the banned Kurdish militant group PKK.

He is also under investigation for "bribery, extortion, corruption, aggravated fraud, and illegally obtaining personal data for profit as part of a criminal organisation".

"Mr Imamoglu denies all the charges against him," one of his lawyers, Mehmet Pehlivan said, after the mayor on Friday was questioned for six hours by police over the graft allegation.

The pro-Kurdish opposition DEM party, which has had 10 of its own elected mayors removed over the past year and replaced by government-appointed trustees has also thrown its support behind the protests.

Addressing the crowds late Friday, CHP leader Ozgur Ozel said 300,000 people had joined Istanbul protest that night.

"Those who provoke our citizens and cause them to clash with our security forces are committing a clear crime," wrote Istanbul governor Davut Gul on X on Saturday.

The move against Imamoglu has hurt the Turkish lira and financial markets, with the stock exchange's BIST 100 index closing down nearly eight percent on Friday.

A.Riccobono--INP