Rights groups tell European court İmamoğlu’s detention is part of wider campaign against Turkey’s opposition

Three rights groups have filed an amicus brief at the European Court of Human Rights in the case of detained Istanbul Mayor Ekrem İmamoğlu, arguing that his detention should be viewed as part of a wider pattern of using criminal law against opposition politicians in Türkiye.

The groups — the Turkey Litigation Support Project, Human Rights Watch and the International Commission of Jurists — said Tuesday they had submitted the third-party intervention in İmamoğlu v. Türkiye. The Strasbourg-based court, the Council of Europe’s human rights court and separate from European Union courts, formally notified the Turkish government of the application on April 13, 2026.

The court is examining claims that İmamoğlu’s detention violates Article 5 of the European Convention on Human Rights, which protects the right to liberty and security; Article 18, which bars using restrictions on rights for ulterior purposes; and Article 3 of Protocol No. 1, which protects the right to free elections.

İmamoğlu is Istanbul’s mayor and one of Türkiye’s best-known opposition politicians. He was re-elected on March 31, 2024. Turkish authorities detained him on March 19, 2025, and, according to Human Rights Watch, a court ordered him held in pretrial detention the same day the main opposition Republican People’s Party, or CHP, designated him as a candidate for a future presidential election. He remains detained and has been suspended from office as mayor while his trial continues.

The charges described in the court’s communication include suspicion of “establishing and leading a criminal organisation,” “accepting bribes,” “interfering with public tenders,” and “unlawfully obtaining personal data.”

In their filing, the three groups said the court should assess İmamoğlu’s case against what they describe as a broader campaign of prosecutions targeting opposition politicians, alongside a weakening of judicial independence in Türkiye. Human Rights Watch said that between March 2025 and August 2026, 43 CHP-run municipalities became subject to judicial proceedings and 31 CHP mayors were detained. The groups also argue that lower courts’ failure to comply with some Constitutional Court decisions has left opposition politicians without meaningful domestic protection.

“Detaining political opponents and perceived dissenting voices to remove them from political life and to silence them has become a familiar playbook in Türkiye,” Ayşe Bingöl Demir of the Turkey Litigation Support Project said in a Human Rights Watch news release.

The case is significant in part because Strasbourg has already ruled on politically sensitive detentions in Türkiye. In its Grand Chamber judgment in Selahattin Demirtaş v. Turkey on Dec. 22, 2020, the court found that the detention of the Kurdish opposition leader pursued the ulterior purpose of “stifling pluralism and limiting freedom of political debate.” That precedent looms over İmamoğlu’s case because Article 18 findings are rare and go to whether criminal proceedings were used for political ends.

Osman Kavala is another prominent Turkish case in which the court found an Article 18 violation.

“In reviewing the legitimacy of Ekrem İmamoğlu’s detention, the European Court of Human Rights will be examining a case that bears many similarities to the detentions of the Kurdish politician Selahattin Demirtaş and others it has already adjudicated,” Aisling Reidy, senior legal adviser at Human Rights Watch, said in the same release.

The intervening groups said the erosion of judicial independence in Türkiye is central to the case now before Strasbourg, arguing that domestic courts no longer provide an effective safeguard for opposition figures challenging detention.