The source, who spoke anonymously due to restrictions on talking to media, said five extremists were detected by a drone in the Cayirli region of the Cukurca district. 

Two other PKK extremists were also killed in the same region in a separate air operation on Wednesday.

The PKK -- listed as a extremist organization also by the U.S., and the EU -- resumed its decades-old armed campaign in July last year. 

Since then, more than 700 security force members have been martyred and around 8,000 PKK extremists killed or apprehended.