"The blast occurred near the house of Mohammad Mohaqiq, deputy to Chief Executive Abdullah Abdullah, in Golah-e-Dawakhana locality, Police District 3 roughly at 6:50 a.m. local time (0230 GMT)," witness Abdul Jalil told Xinhua.
Local media Tolo News, citing sources from Mohaqiq's office, reported that 20 people were killed and more than 20 others wounded by the explosion.
However, it was not immediately known whether Mohaqiq was at the compound when the attack took place. A private university was also located near the site.
Most of the casualties were from people aboard a minibus running on the road when the blast occurred.
The victims were shifted to nearby hospitals.
A thick black smoke was seen rising above the site and several vehicles and nearby houses were also damaged.
No group has claimed responsibility for the attack yet.
Afghan civilians continue to bear the brunt of conflicts as more than 1,660 civilians were killed and over 3,580 others injured in conflict-related incidents across Afghanistan in the first half of the year, according to a report released by the United Nations mission office in the country.
XINHUA/MNA