Five rebel fighters of the banned Kurdistan Workers Party (PKK) were killed and one Turkish security guard was injured in Turkey today.
The clash took place in a heavily forested area near the town of Bingol in Turkey's mainly Kurdish southeast region.
The officials said some 2,000 soldiers were seeking to flush out between 15 and 20 guerrillas in the area. The operation began on Thursday and continued on Friday.
"We expect the number of dead PKK to increase by evening," a military source said.
Separately, a civilian taxi driver in the town of Tunceli was seriously wounded when his vehicle hit a remote-controlled mine planted in a city street, another official said.
Another 3,000 Turkish security forces, backed by helicopter gunships, have undertaken a sweeping operation in Tunceli province.
Security officials have said that a large number of PKK rebels have entered Turkey from Iraq in recent months armed with C-4 plastic explosives used to create homemade mines.