Turkish police early on June 11 raided houses of Peoples' Democratic Party (HDP) officials in the southeastern province of Hakkari.
Among the detained were former HDP Hakkari provincial co-chair Sipan Turan, HDP Hakkari Central district co-chair Sinem Seven, HDP Hakkari Women's Council spokesperson Zeynep Kaya and Şemdinli district co-chair Sozdar Atilla.
The four HDP officials were taken to the Hakkari provincial police station for their testimonies.
HDP Hakkari Central district co-chair İsmail Seven and Yüksekova district co-chair Şadiye Kırmızıgül were also called in to testify.
The latest crackdown on the HDP came as the Court of Cassation's Chief Public Prosecutor earlier this week refiled a closure case against the party.
In a revised 850-page-long indictment submitted to the Constitutional Court, the prosecutor argued that the party closure was an implementation adopted "in all advanced democracies."
The prosecutor demanded a political ban for 451 HDP officials and sought a freeze on the party's bank accounts.
Critics say Turkey's judiciary is under the influence of politics, a claim which the ruling Justice and Development Party (AKP) and its Nationalist Movement Party (MHP) allies deny.
MHP leader Devlet Bahçeli, who has repeatedly called for the closure of the HDP, said the Constitutional Court does not have the option to return the indictment a second time.
"This bloody and dark page should be closed never to be opened," Bahçeli told members of his party on June 8.