A police officer was killed and four others were injured Monday in a terrorist attack in the southeastern city of Diyarbakır, which has long been a hotbed of violence by the PKK terrorist organization.

Doğan News Agency (DHA) reported that an explosive device planted on the wall of a cemetery near the Dicle University campus exploded as a bus carrying policemen was passing by around 4:30 p.m. local time. Ambulances were dispatched to the scene where a thick column of smoke towered above. DHA has reported that the death toll later rose to three, but reports were not yet confirmed at the time Daily Sabah went to print.

An investigation was launched into the incident while Anadolu Agency reported that the PKK was responsible for the attack. The terrorist group, which claims to fight for Kurdish self-rule in Turkey's southeast, has killed thousands in the last three decades in terror attacks across the country. After a brief lull, it renewed its large-scale attacks targeting civilians and security forces, especially in the predominantly Kurdish Diyarbakır province. The police and military launched a counterterror sweep last year in the city and after months of operations, PKK presence in Diyarbakır was largely wiped out although militants are apparently still capable of launching small-scale attacks.