KANDAHAR, Afghanistan (Reuters) - A landmine explosion killed nine children in northeastern Afghanistan on Saturday, an official said, as civilian casualties increased during the conflict.

The blast occurred in Darqad district of Takhar province when children passed over a mine planted on a road in a Taliban-controlled village.

"Nine students were killed this morning after a landmine planted by the Taliban exploded," Takhar Jawad Hijri, a spokesman for the provincial governor, told AFP.

He said the children were aged between seven and 11, and there was no immediate comment from the Taliban on the incident.

Meanwhile, seven people were killed by an explosive device in Paktika province, eastern Afghanistan, according to a security official.

A spokesman for the local police in the province said the explosion was caused by a car hit by a landmine planted on the road in a village, noting that four of the dead were members of the same family, and blamed the Taliban for laying the mine.

Last month, the United Nations published a report saying that an "unprecedented" number of civilians were killed or injured in Afghanistan from July to September this year.

A month ago, seven children were killed and 10 wounded in Laghman province when a shell they were playing with exploded.

The United Nations held "anti-government elements" - such as the Taliban - the bulk of the responsibility.