Nine children have been killed in a roadside blast in north-eastern Afghanistan as they made their way to school.

The children - eight boys and a girl aged between seven and 10 - accidentally stepped on a deliberately-planted mine, officials said.

So far, no one has claimed responsibility for the bomb.

"At 8.30am (04:00 GMT) this morning, tragically, nine school children were martyred in a landmine blast," Jawad Hejri, a spokesman for the Takhar provincial governor, told AFP news agency.

Last May, a landmine killed seven children and wounded two more in the southern province of Ghazni.

In February, seven children were killed and 10 more wounded in Laghman province when a mortar shell exploded as they played with it.