Ankara, Turkey: Turkey's military General Staff said on Sunday 23 Kurdish rebels and 12 Turkish soldiers had been killed in clashes near the Iraqi border.

"The clashes are continuing," the General Staff said in a statement posted on its Web site.

Security sources earlier told Reuters the death toll among Turkish troops was at least 13 following an ambush by rebels of the outlawed Kurdistan Workers Party (PKK).

The soldiers were the first Turkish casualties since the Ankara parliament on Wednesday authorised troops to conduct cross-border incursions into northern Iraq to hunt down rebels using the region as a base.

The incident occurred in mountainous Hakkari province, where large numbers of Turkish forces are deployed to try to prevent rebels of the outlawed Kurdistan Workers Party (PKK) crossing over from Iraqi bases to stage attacks inside Turkey.

"Nine soldiers have been martyred during a clash with the terrorists. Operations are continuing in the area," a security source told Reuters on condition of anonymity.

The United States, Turkey's NATO ally, and the Baghdad government have urged Ankara not to send troops into northern Iraq, fearing this could destabilise the region.

But Prime Minister Tayyip Erdogan's government is under heavy pressure from public opinion and the powerful military to take action against the PKK following a series of deadly attacks on Turkish security forces.

Ankara blames the PKK for the deaths of more than 30,000 people since the group launched its armed campaign for an ethnic homeland in southeast Turkey in 1984. The United States and European Union class the PKK as a terrorist organisation.