A court on Sunday charged two more prominent journalists with links to an alleged plot to topple the Turkish government in a case that has raised worries of media freedom in Turkey.
Ahmet Sik and Nedim Sener, who have written investigative books about Turkey's clandestine "deep state" activities, were detained on Thursday with six other journalists after police raided their homes at dawn. They were jailed pending trial.
Another prominent journalist, Soner Yalcin, who runs a news website critical of the government, was charged last month as part of the same case, which has turned the political heat on the government before elections in June.
The arrests of journalists in Turkey, a country which has applied to join the European Union, has also drawn expressions of concern from the United States, the EU and Human Rights Watch about Ankara's commitment to democratic principles and free media.
Human Right Watch said on Saturday such developments had a "chilling effect" on free speech and urged Prime Minister Tayyip Erdogan's government to respect press freedom.
Authorities say the arrests are part of an investigation into an alleged plot by a murky ultra-nationalist group known as Ergenekon to overthrow Erdogan's AK Party government. But critics say the case is being used to silence media critical of the AK government, which has a huge majority in parliament and controls levers of state power.
Sik is already on trial over a book he co-wrote about the Ergenekon group. He had also written stories in a now-defunct magazine about diaries by a formal navy commander outlining the existence of an alleged coup plan against Erdogan's government.