nhk world hideki yui has more details. >> reporter: a bomb detonated remotely. afghans are dying every day from explosives like these. they killed more than 1,000 people last year. this bomb was constructed by afghan forces. the main ingredient of white powder is ammonium nitrate. set on fire, it becomes explosive. three years ago, the afghan government banned all chemical fertilizers containing ammonium nitrate, but the ban has had little effect. militants smuggle chemicals across the border from neighboring pakistan. 70% of the bombs used in afghanistan are said to be made using fertilizer from pakistan. >> ammonia nitrate coming from pakistan and how much of a concern that is, the ammonium nitrate that is used in i.e.d.s is still a concern to the forces. >> reporter: this shop outside the capital sells fertilizer containing ammonium nitrate. a bag costs about $15. the shop will sell to anyone with money. >> translator: we just sell fertilizer. it's not our fault if our products are put to bad use. >> reporter: fertilizer is widely used in pakistan. it's said