The air raid targeted a cave in the Avasin-Basyan region, which served as a base for a "large group" of Kurdistan Workers' Party (PKK) militants who were preparing for an attack across the border in Turkey, the statement said.

The hideout "was hit successfully" and the warplanes returned safely to their bases, it said, without giving details on any losses among the rebels.

Turkish fighter jets have been bombing PKK positions in the mountains of northern Iraq since December 16.

Ankara estimates that more than 2,000 militants are holed up in Kurdish-run northern Iraq, using camps there as a springboard for attacks on Turkish targets across the border.

The Turkish government has a one-year parliamentary authorisation for cross-border military action against the PKK, which expires in October.

The United States has backed its NATO ally by providing real-time intelligence on PKK movements in Iraq.

The PKK, listed as a terrorist group by Ankara and much of the international community, took up arms for self-rule in Turkey's mainly Kurdish southeast in 1984, sparking a conflict has claimed more than 37,000 lives.

Most recently, the PKK claimed responsibility for a blast at a section of a major oil the pipeline in eastern Turkey on August 5 and threatened more attacks on economic targets in the country.

The blast cut flow through the Baku-Tbilisi-Ceyhan pipleine, which carries Azeri oil to Turkey's Mediterranean port of Ceyhan from where the crude is shipped to the West, causing fresh jitters on world oil markets.

The Turkish authorities have played down the possibility of a sabotage but are yet to say what caused the explosion.

Officials blamed the PKK for two bomb blasts in Istanbul on July 27, which killed 17 people and injured more than 150.