Taliban militants have claimed responsibility for the explosion.
An army officer at the scene said the bomb was placed in a cart on the side of the road and exploded as the bus passed.
"Today at 6:15 a.m. local time, an explosion was caused by the enemies of peace and stability," said Kabul senior police officer Ali Shan Paktiawal. "As a result, 14 people were wounded. Seven of them are Afghan Army officers and seven others are residents of this area or passersby. An investigation is under way, and we will announce the result soon."
Eyewitness Karim Dad described the incident this way: "I was just five meters away from the army bus when the explosion occurred. Suddenly, I heard a huge bang, and I saw smoke rising out of the bus, and the bus was full of officers in a panic."
Senator Gunned Down In Capital
Also in Kabul, Senator Abdul Sabur Farid was gunned down outside his home late on May 2. No group has claimed responsibility for the killing.
The "Hindustan Times" reported that Farid was shot several times from a moving car as he was entering his house in northern Kabul.
Farid served briefly as prime minister under a mujahedin-led government in 1992.
He won a term to represent Kapisa Province in the Afghan upper house, the Meshrano Jirga, in the country's landmark national elections in 2005.
No group has immediately taken responsibility for the killing.
(Reuters, AP, AFP)