Turkey will keep hitting Kurdish PKK fighters in northern Iraq, the foreign ministry said on Saturday, a day after its strikes sparked criticism from Baghdad. The Turkish military said on Friday it killed eight Kurdistan Workers Party (PKK) militants, prompting Iraqi authorities to summon the Turkish ambassador in Baghdad to formally protest the air raids on Iraqs Sinjar and Makhmour mountains. Turkey regularly hits PKK bases across its southern border, saying the militants use the remote and mountainous northern Iraqi region as a base for deadly attacks inside Turkey, where the outlawed group has waged an insurgency since the 1980s. President Tayyip Erdogan threatened to launch a ground offensive in northern Iraq earlier this year. This week he also announced an imminent operation against US-backed YPG Kurdish fighters in neighboring Syria. The YPG, which has been fighting ISIS militants, controls Syrias northeastern border with Turkey. Ankara says it is an extension of the PKK and poses a direct threat to Turkey. "The activities of the PKK terrorist organization in the territory of Iraq and Syria have become a national security issue for Turkey," Foreign Ministry spokesman Hami Aksoy said Saturday. He said the government in Baghdad had a duty to prevent Iraqi land being used as a base for attacks on neighbors, and described Fridays air strikes as an act of self-defense which Turkey carried out because Iraq would not act. "These operations in the fight against terrorism will continue as long as terror organizations nest on Iraqi soil and as long as Turkey’s security needs require it to," Aksoy said.