"Terrorists opened fire on the vehicle" on patrol, governor Zubeyir Kemelek told the Anatolia news agency, without specifying which group the assailants belonged to.

He said a manhunt had been launched. A children's festival due to be held on Monday in the province's main city has also been cancelled for security reasons.

The outlawed Kurdistan Workers' Party (PKK) rebels have been active in the region, which is beyond their regular theatre of operations in the country's Kurdish-dominated east and southeast.

The PKK, outlawed by Turkey and most of the international community, has been fighting for self-rule since 1984 in a bloody conflict that has claimed more than 37,000 lives.

The group has notably stepped up its attacks this year and, in response, the army has launched a large-scale crackdown against the rebels and amassed troops on the border with Iraq, where PKK members take refuge.