Ali Avcu, the editor-in-chief of the Yurt daily, which is highly critical of the Turkish government, was detained on Tuesday evening on insult charges in the northwestern Turkish province of Bolu, Turkish media reports said.
Acting on an arrest warrant, gendarmes took Avcu into custody in Bolu, where he went to attend a meeting.
He was taken to the police station for interrogation.
It was not immediately clear who Avcu was accused of insulting, but it is very frequent for journalists as well as everyday citizens to face charges of insult due to their criticism of Turkish President Recep Tayyip Erdoğan and government officials.
President Erdoğan is accused by his critics of establishing a one-man rule in Turkey, destroying the separation of powers and silencing dissent.
Turkey, where more than 150 journalists and media workers are currently jailed, was ranked 157th among 180 countries in the 2018 World Press Freedom Index released in April by Reporters Without Borders (RSF).