Il Nuovo Postiglione - Istanbul's Imamoglu defiant after government suspends him as mayor

Just four days after his arrest in a pre-dawn raid by hundreds of police, the powerful and popular opposition mayor was stripped of his title and became an inmate at Silivri prison on the megacity's western outskirts.

"This is not a judicial procedure, it's a (political) execution without trial," he wrote on X through his lawyers while being taken to jail after a court formalised his arrest.

His arrest has sparked a massive wave of protest that began in Istanbul but has since spread to at least 55 of Turkey's 81 provinces, according to an AFP count.

Demonstrators were gearing up for another mass show of defiance at 1730 GMT on Sunday night, with the Istanbul authorities moving to close off access roads and bridges leading to City Hall in the historic peninsular.

Although the court decided against formalising his arrest in a separate "terror" probe, the interior ministry said he had been "suspended from office".

The court decisions came as the main opposition CHP party held a long-planned primary to elect Imamoglu as its candidate in the 2028 presidential election.

- 'I won't be bowed' -

"Be sure to vote today for the future of Turkey, then raise your voices by meeting in the squares of Istanbul and other provinces," Imamoglu wrote ahead of a fifth night of mass protest.

Observers said it was the looming primary that triggered the move against Imamoglu, widely seen as the only politician capable of challenging President Recep Tayyip Erdogan.

Earlier he insisted he would fight on.

"We will erase this black stain on our democracy. I will not be bowed."

Throughout the day, voters flocked to ballot boxes in 81 cities after the CHP opened up the poll beyond its 1.7 million party members to anyone who wanted to participate.

Many long queues could be seen outside polling stations in several areas of Istanbul, with the municipality saying the voting hours had been extended until 8:30 pm (1730 GMT) due to "overwhelming turnout".

Polling stations had been due to close at 5:00 pm.

"Whenever there's a strong opponent (to Erdogan), they are always jailed," said 29-year-old voter Ferhat, who declined to give his surname.

"There is a dictatorship in Turkey right now, nothing else. It's politics in name only," he told AFP near City Hall.

Many people expressed anger over the move against a mayor whom they had elected.

"They have literally stolen our vote. It brings tears to my eyes," 70-year-old Sukru Ilker told AFP.

Ilker said protesters didn't want "to confront the police" but did so only to protect the candidate the city had voted for.

Ayten Oktay, a 63-year-old pharmacist, said there was no going back.

"Now the Turkish nation has woken up. The protests will definitely continue after this. We will defend our rights until the end," she said.

- 'A great awakening' -

Casting her ballot early on Sunday, Dilek Kaya Imamoglu urged the country to show its support for her husband.

"We are casting our vote to support President Ekrem -- for democracy, justice and the future," she wrote on X, vowing to "never give up".

Earlier, she met him briefly at the court with CHP leader Ozgur Ozel.

Ozel said the mayor was in good spirits.

"He said this process had led to a great awakening for Turkey, which he was happy about," said Ozel, who put Saturday's turnout at the Istanbul protest at more than half a million.

Riot police used rubber bullets, pepper spray and percussion grenades on the Istanbul protesters. In Ankara, they also used water cannon.

The move against Imamoglu has badly hurt the lira and caused chaos on Turkey's financial markets, where the benchmark BIST 100 index closed nearly eight percent lower on Friday.

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

M.Dodaro--INP