Eighteen inmates of the outlawed Kurdish Workers' Party (PKK) on Wednesday morning escaped from a prison in Bingol province in eastern Turkey, private Dogan news agency reported.

The group, which had been convicted of for being PKK members as well as aiding and abetting lawbreakers, escaped from a M-type prison in Bingol province through a tunnel they had dug, said the report, quoting a police source.

The Turkish security authorities have launched an investigation into the jail break and have informed the nearby provinces to arrest the inmates.

The PKK, listed as a terrorist organization by Turkey and part of the international community, took up arms in 1984 in an attempt to create an ethnic homeland in southeastern Turkey. Since then, over 40,000 people have been killed in conflicts involving the group.