Turkish tanks entered northern Iraq and were heading towards a Kurdish militant camp, Turkish media reported Tuesday.
The army's incursion is part of the reaction to last week's series of attacks by the Kurdistan Workers Party (PKK) in which 24 Turkish soldiers and policemen were killed in the border province of Hakkari, DPA reported.
Turkey responded with air raids on PKK camps in northern Iraq, which it uses as bases to attack Turkey.
The target of the latest operation was a PKK camp in Haftanin, around 20 kilometres over the border.
The PKK has been fighting for independence or greater autonomy for Kurdish regions since the 1980s. Around 45,000 people have been killed in the conflict.
The group is classed as a terrorist organization by Turkey, the European Union and the United States.