The raid was undertaken after "it was determined that a large group of terrorists, who have been watched for a long time, are preparing to pass the winter in eight caves and hideouts in the Zap region", the Turkish general staff said in a statement on its website.

"Our warplanes hit the targets in an effective air raid that started in the morning hours of December 26," it said.

The statement did not mention casualties.

It was the third air strike on Kurdistan Workers' Party (PKK) targets that the Turkish army has confirmed since December 16, in addition to a ground cross-border operation.

Officials in northern Iraq have reported two other air strikes, including one on Tuesday.

"The success achieved in the operations is a clear indication that seasonal conditions, visibility and the nature of the terrain cannot be a hurdle in the Turkish armed forces' struggle against terrorism," the statement said.

The military said Tuesday that at least 150 PKK rebels were killed on December 16 in the largest air strike in northern Iraq so far, when fighter jets bombed positions along the Turkish border and in the Qandil mountains to the east, where the PKK is known to have camps.

It said the strike destroyed more than 200 PKK targets, including command, training and logistical bases as well as anti-aircraft defence positions and ammunition depots.

The PKK, listed as a terrorist group by Turkey and much of the international community, has waged a bloody campaign for Kurdish self-rule in southeast Turkey since 1984. The conflict has claimed more than 37,000 lives.

The PKK has long enjoyed safe haven in Kurdish-run northern Iraq, using camps there as a springboard for attacks across the border on Turkish targets.