Four were killed in a car bomb attack in the centre of the city of Diyarbakir while another three civilians lost their lives in a near simultaneous bombing in Kiziltepe in Mardin province to the south, said the source, who asked not to be named.
Both bomb attacks had been aimed at passing police vehicles, the Dogan news agency said. NTV television said 25 people were wounded in the Mardin attack and 13 people wounded in Diyarbakir.
The authorities believe both blasts have been carried out by the Kurdistan Workers’ Party (PKK), a Turkish official said. Hundreds of members of the Turkish security forces have been killed by the PKK in attacks since the collapse of a two-year ceasefire in July last year.
Earlier Wednesday, five Turkish soldiers were killed in an attack blamed on PKK militants in Uludere in the southeastern Sirnak province close to the Iraqi border.
Over 40,000 people have been killed since the PKK first took up arms in 1984. It is proscribed as a terrorist group by Turkey, the European Union and the United States.
The PKK has kept up attacks after the July 15 failed coup during which a rogue military faction tried to oust President Recep Tayyip Erdogan from power.
The government has vowed there will be no let up in the fight against the PKK even in the wake of the coup.