A previous toll on Sunday had set the number of dead soldiers at three.

Two soldiers and a "village guard", a Kurdish militia member armed by Ankara to fight Kurdish separatists, were killed overnight Saturday to Sunday in clashes with members of the Kurdistan Workers' Party (PKK) in the mountainous Sirnak region that borders Iraq, according to the security source.

A third soldier died when a PKK mine exploded in the eastern Bitlis province, added the source, who asked not to be named.

Meanwhile, three soldiers were killed in fighting with PKK rebels in Yayladag in the eastern Bingol province on Saturday afternoon, the Anatolia news agency reported, adding that a large-scale operation was underway in the area.

Those deaths came after two Turkish soldiers and two Kurdish rebels were killed in clashes in Bitlis on Friday. Four troops were injured in that fighting.

With a total of nine deaths in the past two days, the pro-Turkish troops have suffered their heaviest casualties in months.

The rebels have recently been taking advantage of the end of winter to launch attacks in Turkish territory from their bases in the mountains of northern Iraq, where Ankara's troops cannot strike back at them.

More than 37,000 people have been killed since 1984 when the PKK, which is considered a terrorist organisation by Turkey, the United States and the European Union, took up arms for self-rule in the mainly Kurdish southeast of Turkey.

The PKK announced a ceasefire in October, but Turkish authorities rejected it. Violence related to the conflict has however since dwindled.