The Halk TV journalists were prosecuted in January, accused of broadcasting a secretly recorded interview with a legal expert appointed as part of an investigation into Istanbul's opposition mayor, Ekrem Imamoglu.

"Halk TV chief editor Suat Toktas and journalists Seda Selek, Serhan Asker, Baris Pehlivan and Kursad Oguz have been acquitted," Halk announced on social media.

All five were arrested in late January.

The four reporters were released under supervision, while their chief editor was remanded in custody.

Erol Onderoglu, the representative in Turkey of Reporters Without Borders (RSF) said the acquittal by an Istanbul court was a "relief".

But he said it was worrying that such "arbitrary cases" were continuing.

A number of government critics -- lawmakers, artists, journalists and business executives -- have been prosecuted in recent weeks.

On Tuesday, the mayor of a district of Istanbul who is a member of the opposition social-democrat CHP was removed from his post accused of rigging calls for tender.

More than a dozen mayors from the CHP and the pro-Kurdish DEM who were elected last year have been forced out of office, most of them on accusations of "terrorism".