The soldier was killed during a helicopter-backed offensive against a group of rebels from the Kurdistan Workers' Party (PKK), spotted in Yesilova village of Hakkari province, the sources said.

Wednesday's clash pushed up the number of casualties among Turkish security forces to nine in a month of clashes with militants, while 21 rebels were killed in the same period, according to Turkish officials.

Fighting between the two sides escalates in spring as snow melts along the mountainous Iraqi-Turkish border, allowing easy passage for rebels holed up in rough terrain to launch attacks in Turkey's southeast.

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