The clashes erupted overnight in the mountains of Tunceli province, where the army recently launched an operation against the separatist Kurdistan Workers' Party (PKK), the sources said.

The operation was continuing, they said.

The PKK, listed as a terrorist group by Ankara and much of the world, has waged an armed campaign for self-rule in Turkey's mainly Kurdish east and southeast since 1984, in a conflict that has claimed some 45,000 lives.