"We heard a huge blast in Asamayi road, Police District 2 roughly at 6:15 p.m. (local time) and the whole place has now been sealed off," eyewitness Aman Karimi told Xinhua.
Meantime, an Interior Ministry official told Xinhua that an improvised bomb struck a ministry's vehicle, injuring an Interior Ministry Staff College official.
The injured was shifted to a nearby hospital by a police vehicle. No group has claimed responsibility for the incident.
The official noted that an investigation is underway.
The Afghan capital city with a population of nearly 5 million has been hit by series of terror attacks over the past couple of years.
On Sept. 17, a Taliban suicide bomber struck a crowd near a diplomatic district, killing 22 people including six military personnel and injuring 38 others.