Militants of the separatist Kurdistan Workers' Party (PKK) opened fire at the guard late Sunday and managed to escape, taking advantage of the dark, the sources said, adding that an army operation, backed by air cover, was under way to hunt down the assailants.

The governor's office in Hakkari province, where the attack took place, confirmed the death toll, without giving other details on the attack.

The PKK, whose militants take refuge in mountainous bases in neighbouring northern Iraq, has recently stepped up attacks inside Turkey.

The group, listed as a terrorist organisation by Turkey and much of the international community, took up arms against Ankara in 1984, sparking a conflict that has claimed some 45,000 lives.