“The attack occurred at around 08:30 a.m. local time in Bagh-e-Dawood locality in the western outskirts of Kabul, leaving 10 people killed and four others wounded,” a police official told Xinhua anonymously.
The stricken bus was travelling to neighboring Wardak province.
The casualties were shifted to nearby hospitals by ambulances and police vehicles.
More details would be made public later as investigation is going on, the source added.
Najib Danish, a spokesperson of the interior ministry, confirmed the casualties.
The explosion also damaged nearby houses and shops.
No group has claimed responsibility yet for the attack, but the Taliban insurgent group routinely claims responsibility for such attacks.
The blast came as the Afghan government executed six Taliban members earlier this month. The Taliban condemned the execution and warned to take revenge against the judges.
About 600 civilians were killed and more than 1,340 others wounded in conflict-related violence and Taliban-led attacks in first quarter of the year, according to UN mission in the country.
The mission has attributed 60 percent of the casualties to the Taliban and other insurgent groups, 19 percent were attributed to security forces while the rest 21 percent of civilian casualties were unattributed or caused by explosive remnants of war. Endit