The blast happened in the northeastern province of Takhar. Saturday is a school day in Afghanistan.
“This area is under Taliban control and since security forces launched attacks to clear it, the Taliban have planted anti-personnel mines,” Khalil Asir, a spokesman for the provincial police, told Reuters.
“Unfortunately, today, one of those mines exploded and killed nine primary school students,” he said.
The children, aged nine to 12, included four from what Asir described as a “Taliban family”.
Civilian casualties have been increasing to record levels in Afghanistan this year.