Around 20 journalists are believed to have been arrested in a series of dawn raids in Turkey.
According to World Association of Newspapers and News Publishers (WAN-IFRA) police attempted to raid the offices of the Zaman daily but were repelled by protesters who had gathered to support the newspaper.
The paper's editor-in-chief, Ekram Dumanli, is said to have challenged the police to arrest him and was later detained, along with Hidayet Karaca, head of the Samanyolu Media group. According to WAN-IFRA some two-dozen journalists, producers, scriptwriters, directors, police officers and two former police chiefs have also been arrested.
They are accused of forming and belonging to an illegal organisation with close ties to US-based Islamic cleric Fethullah Gülen, a leading critic of President Erdogan.
WAN-IFRA said in a statement: "The use of dawn raids to intimidate journalists while having the police enter the premises of media organizations sends a chilling message to the rest of society that criticism will not be tolerated.
"Given Turkey's record of imprisoning journalists, we are deeply concerned that many of those arrested could face lengthy prison terms."