In the attack late Saturday, rebels from the outlawed Kurdistan Workers' Party (PKK) opened fire with assault rifles on the soldiers who were on a security sweep around Lice town in Diyarbakir province, added the source, speaking on condition of anonymity.

An operation was underway to catch the assailants.

The ambush came a day after PKK rebels attacked a military outpost in the eastern province of Tunceli, killing four soldiers and wounding seven.

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

The arrival of spring usually brings a resurgence of violence as the rebels move out from their mountain hideouts in Turkey and neighbouring Iraq when the snow melts.