"Four fighters were killed and five wounded in largescale Turkish air raids on Thursday," Ahmed Denis, a spokesman for the Kurdistan Workers' Party (PKK) in northern Iraq, told AFP.

About 20 fighter jets took part in the operation which targeted PKK positions in the Zap-Khakurk region of the Kurdish-held autonomous north of Iraq, according to Turkey's NTV news channel.

In the second such operation this month, nearly 50 targets were hit in day-long missions carried out mainly on intelligence passed on by the United States, it said.

Turkey's Anatolia news agency said the strikes were ordered after a group of PKK rebels were detected on their way towards the Turkish border from their mountain hideouts in northern Iraq.

The region's Iraqi Kurdish regional presidency, in a statement, on Saturday condemned the air strikes as a violation of Iraqi sovereignty.

"We call for the military operations to stop immediately and we call on them (PKK and Ankara) to settle their differences through dialogue, to find a solution because the use of violence... will not bring a solution," it said.

Thursday's strikes followed a series of PKK attacks in May on Turkish military targets in southeast Turkey that killed several soldiers.

On May 7, Turkish warplanes bombed and destroyed PKK positions across the Iraqi border from which the rebels were firing on Turkish helicopters, according to the Turkish military.

The PKK, blacklisted as a terrorist organisation 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 that has cost 45,000 lives.

The arrival of spring usually brings a resurgence of violence as the rebels move out from their mountain hideouts in Turkey and neighbouring Iraq when the snow melts.

The Turkish army has staged a series of air raids against PKK bases in northern Iraq since December 2007, often with the help of US intelligence, and in February 2008 carried out a week-long ground incursion.

Ankara says about 2,000 PKK rebels are holed up in the mountains of northern Iraq, from where they launch attacks on Turkish territory.