Asadullah Dawlatzai, a spokesman for the provincial governor, says eight other children were wounded Sunday near the provincial capital, Mihterlam.
He speculated that either a bomb recently planted by insurgents or leftover unexploded ordinance could have caused the blast.
He said all the casualties are between 7 to 15 years of age and at least four were reported in serious condition.
No one immediately claimed responsibility for the explosion.
Insurgent groups frequently use roadside bombs to target government officials or Afghan security forces across the country.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)