Turkish security forces have killed at least nine fighters affiliated with the Kurdistan Workers Party (PKK) in two air strikes in southeastern Turkey and another in northern Iraq, according to local government and military officials.

In a statement on Friday, the governor's office in Siirt province said gendarmerie and police units killed three fighters in an air strike in Cevrimtepe village in Baykan district.

The slain fighters were suspected of being behind the assassination attempt on Mehmet Kocabey, Baykan district head, on July 7 and the death of a gendarmerie station commander on July 24.

Later, in a news conference, Ali Fuat Atik, Siirt's governor, said that one of the fighters killed was a former Siirt municipality employee who had been laid off by a government-appointed trustee.

In another statement, the Turkish armed forces said three fighters were killed in a separate air strike in Karadag in Hakkari's Semdinli district.

Later on Friday, three more fighters were killed in a cross-border air operation in Avasin-Basyan region in northern Iraq, the military said.

The air strikes also destroyed ammunition depots used by the PKK, it said.

The PKK launched an armed struggle against the Turkish state in 1984, leaving more than 40,000 people dead.

It is designated as a "terrorist" group by Turkey, the EU and the US - a label it rejects.

A ceasefire between the PKK and the state broke down in July 2015.

Since then, it has been blamed for the deaths of more than 1,200 Turkish security personnel and civilians.