"We have information that new (Turkish) troops are being gathered along the border," said Ahmed Danis, spokesman for the Kurdistan Workers' Party (PKK).

"We expect Turkish troops to launch a new incursion into northern Iraq. The PKK is ready to confront any Turkish aggression."

Danis said Turkish aircraft launched a raid early on Saturday in the Khwarkuk district along the border with Turkey, the second such attack in two days.

The raid lasted for an hour from 6:00 am (0300 GMT), Danis said.

The Turkish general staff said on its website the raid targeted PKK rebels in the Zap, Avashin and Khakurk regions.

"All planes returned to base safely after successfully executing their mission," it added.

Turkish forces have targeted PKK positions in northern Iraq since mid-December, and on Friday Turkish planes also bombed Kurdish rebel hideouts.

In February the army conducted a week-long ground offensive against PKK hideouts in the region, where Ankara estimates more than 2,000 militants are holed up.

The Turkish government has a one-year parliamentary authorisation, expiring in October, to launch cross-border raids.

The United States has backed military action against the rebels by providing Turkey with real-time intelligence on PKK movements.

Listed as a terrorist group by Turkey and much of the international community, the PKK has been fighting for self-rule in Turkey's mainly Kurdish southeast since 1984 in a conflict that has claimed more than 37,000 lives.