The fighting erupted Monday afternoon during a military operation in the mountains of Sirnak province against the separatist Kurdistan Workers' Party (PKK).

Fighting in the region continued Tuesday, the Anatolia news agency said.

With an increase last year in PKK violence, the Turkish army stepped up action against the outlawed group and in February conducted a week-long ground offensive against camps in northern Iraq where the rebels enjoy refuge.

In the latest cross-border operation last week, at least 15 PKK members were killed in two days of air and artillery shelling, the Turkish army said.

The PKK, listed as a terrorist group by Ankara and much of the international community, has fought for self-rule in Kurdish-majority southeast Turkey since 1984. The conflict that has claimed more than 37,000 lives.