ANKARA — An Istanbul court arrested a prominent journalist early Thursday pending trial, amid a fresh clampdown against the Turkish government's critics. 

Journalist Suat Toktas, who is the editor-in-chief of the main opposition-linked Halk TV, was arrested by order of an Istanbul court for secretly recording and broadcasting a phone interview with an expert witness, Turkey’s state-run Anadolu news agency reported.

Earlier this week, Istanbul Mayor Ekrem Imamoglu disclosed the name of the expert witness, claiming he was cherry-picked by the authorities in investigations launched against the main opposition Republican People’s Party (CHP). Two district mayors in Istanbul with the CHP were arrested last month in what government critics slammed as politically motivated trials. In the phone interview, the expert witness is heard denying Imamoglu’s claim and saying he didn’t want to answer questions.

Five journalists were detained as part of the investigation into the broadcast of the interview. Four of them — Baris Pehlivan, Kursad Oguz, Seda Selek and Serhan Asker — were released under judicial control.