ISTANBUL (AP) — Hundreds gathered in Istanbul on Thursday to protest the arrest and removal from office of a mayor of Turkey's largest opposition party over alleged ties to a banned Kurdish militant group.

Ahmet Ozer, mayor of Istanbul's Esenyurt district and a member of the Republican People's Party (CHP), was arrested on Wednesday by anti-terrorism police for his alleged ties to the Kurdistan Workers' Party (PKK).

The Turkish government on Thursday replaced Ozer with Istanbul's deputy governor, a move that CHP chief Ozgur Özel and other politicians called a “coup.”

The mayor's arrest comes as Turkey debates an interim peace process to end a 40-year conflict between the PKK and the Turkish state that has left tens of thousands dead.

Protesters filled a square in Esenyurt after the government banned a rally in front of the municipal building. Some carried banners that read: “(We want) an elected mayor, not an appointed mayor” and called for President Recep Tayyip Erdogan's government to resign.

“In our view, this (government), violating the law and violating the constitution, has carried out a political coup. We will never accept it,” said Tulay Hatimogullari, leader of the pro-Kurdish Peoples' Equality and Democracy Party, whose supporters joined the rally in a show of solidarity.

Özel, whose CHP made significant gains in local elections earlier this year, called for early elections.

Ozer, 64, is a former academic originally from Van in eastern Turkey. In local elections in March, he was elected mayor of Esenyurt, a western suburb on Istanbul's European side.

The Istanbul Prosecutor General's Office said an investigation found that Ozer maintained contacts with PKK figures for more than a decade, according to state-run Anadolu Agency.

Politicians and members of Turkey's pro-Kurdish movement have often been attacked over alleged ties to the PKK, which is considered a terrorist organization by Turkey, the United States and the European Union.

Lawmakers were stripped of their parliamentary seats and mayors were removed from office. Since 2016, several MPs and thousands of party members have been imprisoned on terrorist charges.

Other opposition parties remained largely unscathed, but the CHP mayor of Istanbul, Ekrem ImamogluHe is currently appealing against a prison sentence and a political ban imposed by a court in December 2022 for “insulting” members of the Turkish electoral board in 2019.

Imamoglu accused Erdogan's government of “planning a dirty game” to wrest Esenyurt municipality from the opposition “by declaring (Ozer) a terrorist for fictitious reasons.”