ANKARA: Turkish authorities have detained 343 people during overnight protests in several cities against the detention of Istanbul Mayor Ekrem Imamoglu, the Interior Ministry said on Saturday.
Demonstrations took place in more than a dozen cities including Turkiye's biggest city Istanbul and the capital Ankara, the ministry said in a statement.
It said the detentions were made to prevent “disrupting of public order” and warned that authorities would not tolerate “chaos and provocation".
Tens of thousands of Turks have taken to the streets in mostly peaceful demonstrations since Wednesday, when Imamoglu was detained on charges such as graft and aiding a terrorist group. He is President Tayyip Erdogan's main political rival who leads him in some opinion polls.
The mayor's Republican People's Party (CHP), the main opposition, condemned the move as politically motivated and urged supporters to demonstrate lawfully.
The 53-year-old mayor, who was arrested just days before the CHP was to name him their candidate for the 2028 presidential race, was speaking to police on Saturday morning in connection with the "terror" probe, party sources told AFP.
He was then expected to appear before prosecutors at Caglayan courthouse at 1800 GMT to be questioned in both the graft and the terror probes, they said.
Already named in a growing list of legal probes, Imamoglu — who was resoundingly re-elected last year — has been accused alongside six others of "aiding and abetting a terrorist organisation" — namely the banned Kurdish 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" along with 99 other suspects.
He was questioned by police for six hours Friday about the graft allegations, the party said.
"Mr Imamoglu denies all the charges against him," one of his lawyers, Mehmet Pehlivan said.
"The detention was aimed at undermining Mr Imamoglu's reputation in the eyes of society," he wrote on X early on Saturday, saying both probes were "based on untrue allegations" and "a violation of the right to a fair trial".
Demonstrators across the country were due to rally again on Saturday night.
In a message on X sent via his lawyers, Imamoglu said he was "honoured and proud" of the demonstrators who hit the streets in more than 50 of Turkiye's 81 provinces, saying they were "protecting our republic, our democracy, the future of a just Turkiye, and the will of our nation".
Addressing the crowds outside City Hall in Istanbul on Friday night, Ozgur Ozel, who heads the main opposition CHP, said 300,000 people had joined the demonstration in defiance of a protest ban and a sharp warning from Erdogan that Turkiye would not tolerate "street terror".
As he spoke, the crowd cheered and applauded, waving flags and banners and chanting slogans like: "Don't stay silent or it will be you next".
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.