The soldiers were on a security sweep in a mountainous region near the town of Beytussebap, in Sirnak province which borders Iraq, when they came under fire from Kurdistan Workers' Party (PKK) rebels late Wednesday, the source said.

An operation was underway to catch the attackers.

Aided by US intelligence, Turkey has carried out several air strikes against PKK camps in northern Iraq since December as well as a week-long ground incursion in February.

Ankara charges that more than 2,000 rebels take refuge in the Kurdish-run autonomous north of Iraq where it says they obtain weapons for attacks across the border in Turkey.

The PKK, which is listed as a terrorist group by Turkey and several Western countries, has been fighting for self-rule in Turkey's mainly Kurdish southeast since 1984. The conflict has claimed more than 37,000 lives.