Turkish police carried out raids on a newspaper and TV station, arresting at least 23 people.
Both media outlets are accused of being linked to the exiled Islamic cleric, Fethullah Gulen, who is based in the USA.
Journalists, scriptwriters, producers and a police chief were detained by the Turkish authorities, following the issuing of an official arrest warrant.
All 23 of the detainees have been accused of forming an illegal organisation, interested in bringing down the state.
One of the detainees was Ekre Dumanli, the editor-in-chief of Zaman. Police tried to raid the offices of
Police tried to raid the offices of Zaman, one of Turkey's biggest newspapers, but was forced back by a large crowd of protestors.
A second raid was launched and Dumanli was arrested. Dumanli reportedly smiled and handed over his documents before he was led away by police.
He allegedly told the crowd: "Let those who have committed a crime be sacred. We are not scared."
It has been reported that a Twitter user, known as Fuat Avni, notified staff at Zaman about the police raid prior to the incident. Whilst the Zaman offices were raided, protestors began chanting, "free press cannot be silenced" and attempted to stop police from arresting the editor as he left the building.
The news of the arrests comes after President Recep Tayyip Erdogan declared on Saturday that he would "bring down the network of treachery and make it pay". He said he would hunt Gulen's supporters from their "lairs". He has previously described them as terrorists and traitors.
Fethullah Gulen and Recep Tayyip Erdogan were once close allies before Erdogan accuse Gulen's supporters, the Hizmet movement, of trying to bring him down from power.
Mr Gulen has been living in self-imposed exile in Pennsylvania since 1999, fearing he would almost certainly be arrested if he returned to Turkey. Influenced by Anatolian Sufism, Gulen is believed to have a vast number of supporters, thought to be in the millions from 150 countries.
Influenced by Anatolian Sufism, Gulen is believed to have a vast number of supporters, thought to be in the millions from 150 countries.