Turkish army air strikes against PKK killed three in northern Iraq, while nine more were killed in a separate operation carried out in eastern Turkey.
At least 12 PKK terrorists were killed in two separate operations in eastern Turkey and northern Iraq on Thursday, according to the Turkish military.
A counterterrorism operation in eastern Van province's Caldiran district left nine PKK members dead during a clash with security forces, the military added.
A Turkish soldier was also killed in the province on Thursday.
Three PKK terrorists were killed in air strikes in northern Iraq's Metina area, the Turkish General Staff said.
The strikes also destroyed the PKK's ammunition depot.
The PKK is recognised as a terrorist organisation by Turkey, the US and the EU.
The group resumed its armed campaign against Turkey in July 2015.
Since then, it has been responsible for the deaths of around 1,200 people, including several women and children.
PKK attacks have killed 793 security personnel and injured 4,000; also killing 314 civilians and injuring over 2,000.
More than 10,000 PKK members have been killed or apprehended in anti-terror operations, according to authorities.
About 5,500 weapons, 652,000 rounds of ammunition, over 142 tonnes of explosives, and 15,000 bombs have been seized.