The clashes occurred in a rural area of Sirnak province on Turkey's border with Iraq, a local security source said.

Soldiers opened fire against a rebel group while on a mission to prevent the infiltration of rebels from Iraqi Kurdistan, where the PKK has rear bases.

The PKK, which declared a unilateral truce in August 2010, threatened last month to call it off, denouncing a lack of dialogue with the Turkish government.

The PKK had said it would not be the first to attack while vowing to defend itself "more effectively" against Turkish army operations.

In return it demanded an end to all military operations against the PKK, the easing of prison conditions for its jailed leader Abdullah Ocalan and the release of other detained Kurdish politicians.

Fighting in Kurdish-dominated Anatolia, in southeastern Turkey, has lessened significantly since the truce, which the PKK had extended in November until general elections expected in June to push for a peaceful solution of the 26-year-old conflict.

The PKK, listed as a terrorist group by Turkey and much of the international community, took up arms for Kurdish self-rule in 1984, sparking a conflict that has claimed some 45,000 lives.