The Turkish Government started its largest cross-border incursion into northern Iraq in three years yesterday, following deadly clashes with Kurdish rebels that left 24 security forces dead and 18 wounded.

The advance followed weeks of activity on the border, where Turkish troops have been massing in preparation for a cross-border raid that some experts say is meant to wipe out the Kurdistan Workers' Party (PKK). It came after 200 rebels launched attacks on military outposts and police stations near the border towns of Cukurca and Yuksekova.

After the initial rebel attack, 600 Turkish mountain commandos backed by helicopter gunships pursued the PKK fighters several kilometres across the border back into northern Iraq, where the rebels have camps in the remote Qandil Mountains. A PKK affiliated website said at least five fighters died.

Responding to the PKK attacks, the Turkish President, Abdullah Gul, vowed to "finish" the rebels, saying "the vengeance for these attacks will be great".

"We will never bow to any attack from inside or outside Turkey," the Turkish Prime Minister, Recep Tayyip Erdogan, said. There was no comment in Baghdad, after a warning from the Turkish authorities last week that their patience was running out and that Iraq should deal with the rebel bases near the border at once.

The PKK has been fighting a 30-year war for Kurdish autonomy in southeast Turkey. At least 45,000 people have been killed in the conflict.

In recent months, the Turkish Government has arrested thousands of Kurds across the country, including some elected officials, often on questionable evidence. After a lull, the PKK resumed attacks, claiming the Turkish Government has backed away from an agreement offered by the group's leader, Abdullah Ocalan, who has been imprisoned by Turkey since 1999.

Others, however, felt the attacks were related to ongoing unrest across the region. "Whoever supports terror secretly or openly, they all should know that Turkey will be following them and they'll pay for that," said Erdogan.

"The latest attack clearly proves that PKK became a sub-contractor of some," he said, implying the PKK was controlled by an unnamed regional organisation.

In the past weeks, Turkey has broken with its traditional allies Iran and Syria. Following popular uprisings in Syria and a repressive crackdown by the Assad regime, Turkey sided with its Nato allies and even allowed the Syrian opposition to organise on its soil.

- INDEPENDENT