Turkish warplanes have conducted an anti-terror operation against PKK positions in Northern Iraq, leaving three terrorists dead, military sources said late Sunday.

A cave and two emplacements for machine guns were also destroyed during the operation, sources added.

The terrorists were planning to attack Turkish military positions on the Iraqi border.

"Turkish warplanes have returned to their bases safely," the sources concluded.

The PKK, which is listed as a terrorist organization by Turkey, the U.S. and the EU, broke the ceasefire unilaterally and resumed its armed campaign in July 2015 after a brief reconciliation period.

Since that time, the PKK has been responsible for the deaths of some 1,200 security personnel and civilians, including women and children, while more than 4,000 security personnel and over 2,000 civilians have been injured.

During its more than 30-year terror campaign against Turkey, more than 40,000 people have lost their lives.