At least two explosions were heard near the scene and 10 were killed, said Asif Shinwari, an education department spokesman. At least 10 people were also reported wounded but the final casualty toll could be much higher.
It was the third major attack in less than two weeks in Jalalabad, the main city of Nangarhar province, following a blast that killed a group of Sikhs on July 1 and a second that killed at least 12 people on Tuesday.
There was no immediate claim of responsibility for Wednesday's attack but both previous assaults were claimed by Daesh terrorist group.
Nangarhar province, on the border with Pakistan, has been the main stronghold for Daesh (also known as ISIS ) militants since the movement first appeared in Afghanistan almost four years ago.
