Anti-terror police today detained the 32 journalists and other employees in raids on the offices of pro-Kurdish news agency Dicle (DIHA), Kurdish-language newspaper Azadiye Welat, Aram Publications and KURDI-DER (Kurdish language association).
All were released today after being questioned by police, the sources said.
It was not clear what they were accused of but one source said police had conducted the raid to search for a suspected terrorist who was thought to be hiding inside the DIHA building, which also houses Azadiye Welat.
The Turkish government has been waging a relentless offensive against strongholds the outlawed Kurdistan Workers' Party (PKK) in the southeast and in neighbouring northern Iraq.
In response the group -- blacklisted as a terrorist organisation by Turkey and much of the international community -- has hit back hard, killing dozens of police and soldiers in almost daily bomb and gunfire attacks.
In recent weeks, the authorities have carried out a string of arrests of journalists, and police have raided a holding company that owns opposition media, sparking criticism from Western countries and media watchdogs.