The operation was the most significant yet against supporters of US-based Fethullah Gulen, a former ally of Erdogan who the Turkish strongman accuses of running a parallel state from abroad.
At least 27 people were detained in raids across Turkey, including Ekrem Dumanli, the editor-in-chief of the Zaman daily newspaper which is closely linked to Gulen.
Those held include an executive of Samanyolu television, also seen as close to Gulen, as well as a TV director, producers, scriptwriters and some police officers.
Anatolia said detainees were accused of a number of offenses including "using intimidation and threats" to "form a gang to try and seize state sovereignty", "forgery" and "slander."
More From This Section
Clearly expecting the arrest of Dumanli, some 2,000 supporters and journalists gathered outside Zaman's offices on the outskirts of Istanbul, preventing the police from entering the building.
Those present included the former Turkish football star Hakan Sukur who was once an MP for the pro-Erdogan ruling party but then aligned himself with Gulen.
But plain clothes officers returned a few hours later, detaining a defiant Dumanli, who was applauded as a hero as he was led away by the police through the dense and angry crowd of supporters.
"Let those who have committed a crime be scared. We are not scared," Dumanli said.
The crackdown came almost a year to the day after Erdogan's government was rocked by stunning corruption allegations that the authorities denied and blamed on Gulen.
The corruption probe, opened on December 17, 2013, saw the arrests of dozens of leading businessmen and political figures close to Erdogan -- then prime minister.
The president, accused by critics of becoming increasingly authoritarian, managed to stall the investigation by sacking thousands of police and scores of judges and pushing through laws tightening state control over the judiciary and the Internet.