A large explosion has gone off near a bus station in the southern Turkish city of Diyarbakir, with ambulances on the scene and reports of "many casualties" in Turkish media.
According to the state-run Anadolu news agency four people were killed and 14 wounded. Security sources said the car bomb was targeting a bus transporting police special forces.
The private Dogan news agency reported the same toll and attributed the cause of the explosion to a car bomb. The agency blamed "terrorists" for the incident, using the government designation for Kurdish rebels.
Diyarbakir is the largest city in Turkey's mainly Kurdish southeast and has been hit by waves of violence in fighting between the outlawed Kurdistan Workers Party (PKK) and the government.
Turkey's security forces are engaged in an operation against Kurdish rebels from the PKK in the region. Security sources told AFP news agency the bomb exploded as a police armoured vehicle drove past.
The attack came as Prime Minister Ahmet Davutoglu was due on Friday to make a rare visit to Diyarbakir.
Additional reporting by wires
