A total of nine PKK terrorists, who were planning to carry out an attack, have been killed in a counterterror operation conducted in northern Iraq's Zap region, military sources said Friday.

"The warplanes taking part in the operation have returned to their bases in safety," sources elaborated the airstrike.

The PKK, listed as a terrorist organization by the U.S. and EU, resumed its nearly 40-year armed campaign against the Turkish state in July 2015.

Since then, over 600 security personnel, including troops, police officers and village guards have been killed along with more than 7,000 PKK terrorists in operations across Turkey and northern Iraq.