Two of the rebels were killed near Uludere in Sirnak province, close to the Iraqi border, in a security operation launched late Saturday after a roadside bomb blast blamed on the Kurdistan Workers' Party (PKK) which did not cause casualties, said the source, speaking on condition of anonymity.

A third rebel was killed in Beytussebap, also in Sirnak, in a clash that erupted after a group of PKK militants fired on a police checkpoint.

On Friday, PKK spokesman Ahmed Denis said the rebels had ended a unilateral truce with Turkey -- in place since April 2009 -- "because of Turkey's continuing hostility to the Kurdish people".

The statement came against a backdrop of rising violence between Turkish forces and the PKK which operates out of bases in Turkey and neighbouring northern Iraq.

In one of the bloodiest attacks in recent months, the PKK fired rockets at a navy base in southern Turkey on Monday, killing six soldiers and wounding seven.

The PKK, listed as a terrorist group by Turkey and much of the international community, took up arms in 1984 for self rule in Turkey's Kurdish-majority southeast, sparking a conflict that has claimed some 45,000 lives.