Clashes between Turkey’s security forces and militants from the Kurdistan Workers' Party (PKK) have left four civilians dead in the southeastern part of the country.

The clashes occurred early Friday in Beytussebab district of Sirnak Province when the Kurdish militants launched simultaneous attacks on police and gendarmerie command posts there.

The dead, who were caught in the fighting, include an ambulance driver killed in Beytussebab and three others that were injured by mortar shells. They later succumbed to their injuries at hospital, security sources said on Saturday.

The skirmishes took place a day after two Turkish soldiers as well as 34 Kurdish militants died in the region.

In a separate development on Saturday, the Turkish air force said its jets hit PKK shelters and depots in northern Iraq.

Turkey has been engaged in one of its biggest security operations in the southern border region in the recent past. The Turkish military has been conducting offensives against alleged positions of the Takfiri Daesh terrorists in northern Syria as well as those of the PKK in northern Iraq and southeastern Turkey.

The security operations began in the wake of the deadly July 20 bombing in the southern Turkish town of Suruc, an ethnically Kurdish town located close to the Kurdish town of Kobani on the other side of the border in Syria, where over 30 people died. The Turkish government blamed Daesh for the bombing. On July 22, the PKK claimed responsibility for the killing of two Turkish police officers, saying they were cooperating with Daesh.

The PKK has been fighting for an autonomous Kurdish region inside Turkey since the 1980s. The conflict has left tens of thousands of people dead.

The group now says it is fighting to gain greater Kurdish autonomy. Turkey, the European Union and the United States designate the PKK as a terrorist organization.

Turkish President Recep Tayyip Erdogan has vowed that the fight with the PKK will continue until “not one terrorist is left.”