Eighteen inmates detained for suspected links with the outlawed Kurdistan Workers' Party (PKK) on Wednesday tunnelled their way out of a prison in eastern Turkey, the justice minister said.
Four of the fugitives had already been convicted and the remainder were being held, charged with "membership of a terrorist organisation," Sadullah Ergin said.
The jailbreak sparked a police operation to track down the escaped prisoners after the incident in the Bingol province.
The PKK, listed as a terrorist group by Turkey, the United States and the European Union, took up arms in the Kurdish-majority southeast of Turkey in 1984, sparking a conflict that has claimed about 45,000 lives.
Turkey has recently entered into a peace process with the Kurdish rebel movement after months of clandestine negotiations between the PKK's jailed leader Abdullah Ocalan and the Turkish secret service.
Ocalan declared a truce in March.
But the process has been fragile and Kurdish rebels announced this month they had halted their pullout from Turkey, accusing the government of failing to deliver on the promised reforms to enhance the rights of the estimated 15 million Kurds in the country.
Prime Minister Recep Tayyip Erdogan's Islamic-rooted Justice and Development Party (AKP) is putting the final touches on a long awaited "democratisation package" of reforms which will be unveiled on September 30.