The source said Tahir Elci, head of the bar in the southeastern city and campaigner for Kurdish rights, was arrested over an interview to CNN Turk last week in which he said the outlawed Kurdistan Workers Party (PKK) "is not a terrorist organisation".

On Tuesday he was being questioned by anti-terrorist prosecutors. Being a "terror apologist" is punishable by jail under Turkish law.

"This scene clearly shows the state of freedom of expression in Turkey today," Cihan news agency quoted Elci as saying as he was taken away by police.

"Is Turkey a country of freedom, a democratic country? This scene shows what it is."

In the interview, Elci sparked anger from other CNN Turk guests by saying: "The PKK is a political movement which has important political demands and which enjoys widespread support, even if some of its actions are of a terrorist nature."

The separatist PKK, which launched an uprising against the Turkish state in 1984 which has left over 40,000 people dead, is considered a terrorist organisation by Turkey, the United States and the European Union.

The government began peace talks in 2012 with the imprisoned head of the PKK, Abdullah Ocalan, but the negotiations fell through in the run-up to the general election in July.

Kurdish fighters began staging almost daily attacks against security forces, shattering a two-year truce and killing more than 150 Turkish police and soldiers.

The government meanwhile claims to have killed more than 1,700 Kurdish militants in a relentless bombing campaign.

On October 10, the PKK announced a truce for the run-up to fresh elections on November 1, but clashes between the two sides continue in the southeast.