The PKK, which has fought a decades-long insurgency against the Turkish state, has several positions in Iraq's northern Kurdistan region, which also hosts Turkish military bases used to strike Kurdish insurgents.

"When the Iraqi border forces were carrying out their duties securing the Iraqi-Turkish border... they were fired at by terrorists from the banned PKK organisation" in Zakho district, the interior ministry said in a statement.

The two guards were killed and a third wounded, it added.

The ministry later announced, according to the official news agency INA, that two of the PKK members "who attacked the patrol" were killed during "search operations in the area in pursuit of the perpetrators".

A border guard official told AFP that the guards were patrolling a village near the Turkish border when "shooting and clashes" with the PKK broke out.

Baghdad deploys federal guards along its border with Turkey in coordination with the government of the autonomous Kurdistan region and its forces, the peshmerga.

The Iraqi federal authorities in Baghdad have recently sharpened their tone against the PKK. Last year, Baghdad quietly listed the group as a "banned organisation" -- though Ankara demands that the Iraqi government do more in the fight against the militant group.

Turkey along with the United States deems the PKK a "terrorist" organisation.

Turkey has conducted hundreds of strikes against PKK fighters in Iraq's Kurdistan region.