The landmine, believed to have been planted by Kurdistan Workers' Party (PKK) militants, exploded as a military convoy was passing a road linking the towns of Cizre and Sirnak, close to the border with Iraq.

An earlier toll from the explosion stood at five wounded.

The army launched an operation against PKK rebels in the area after the blast.

Landmine attacks against security forces have recently become a hallmark of PKK violence in the mainly Kurdish southeast.

The PKK, listed as a terrorist organisation by Ankara and much of the international community, has been fighting for Kurdish self-rule in the region since 1984. The conflict has claimed more than 37,000 lives.