Afghan authorities say two roadside bombs have killed 14 civilians in the south of the country.

Officials in Kandahar province said a minivan ran over one bomb in the Arghistan district. Soon after, civilians riding on a tractor arrived to help the wounded and struck a second bomb on the road. It is not known how many people were killed in each blast.

Police blame Taliban insurgents for the explosions.

Also Sunday, NATO said six of its service members were killed in an improvised explosive device attack in eastern Afghanistan. It did not release the names or nationalities of the victims.

The United Nations says 3,021 civilians were killed in Afghanistan last year, the vast majority by Islamic insurgents.