Three of the injured in Diyarbakir were members of the security forces, the sources added. Turkish forces are engaged in an operation against Kurdish rebels from the outlawed Kurdistan Workers Party (PKK) in the region.
Security sources told AFP the bomb exploded as a police armoured vehicle drove past. The attack came as Prime Minister Ahmet Davutoglu, whose government has waged a relentless campaign against PKK rebels since last summer, was due on Friday to make a rare visit to Diyarbakir.
Hundreds of security forces members have been killed since the PKK resumed its more than three-decade insurgency after a fragile truce collapsed last summer.
President Recep Tayyip Erdogan said this week that 355 members of the security forces had been killed in the fighting, along with 5,359 members of the PKK. It was not possible to confirm the toll on the rebel side.
Over 40,000 people have been killed since the PKK took up arms in 1984 demanding a homeland for Turkey’s biggest minority. Since then, the group has pared back its demands to focus on cultural rights and a measure of autonomy.
A radical PKK offshoot, the Kurdistan Freedom Falcons (TAK), claimed responsibility for two suicide car bombings in Ankara this year that left dozens dead.