Hasan Raza Yousafi, a provincial council member, said the target of Sunday's suicide attack was an intelligence unit compound in Ghazni, the capital of the province of the same name.
At least eight members of the National Directorate of Security (NDS) were killed in the blast and 50 civilians were wounded, Afghan government officials said.
Zabihullah Mujahed, Taliban spokesman, claimed responsibility, saying: "Dozens of NDS officers were killed or wounded."
The attack comes as an all-Afghan two-day conference that includes the Taliban begins in Doha in an effort to find an end to the country's 18-year war.
US peace envoy Zalmay Khalilzad said the latest round of talks with the Taliban, also in Doha, were the most productive ever.
Source: Al Jazeera