NATO officials say 250 tons of suspected bomb-making material has been seized in a raid in Kandahar, a stronghold of Taliban insurgents in southern Afghanistan.

In a statement Tuesday, military officials said Afghan National Police and NATO forces recovered 500,000 pounds of ammonium nitrate fertilizer, which is often used in explosives, and 5,000 components used in making roadside bombs. Fifteen people were detained after the raid Sunday at a warehouse. Another 4,000 100-pound bags of fertilizer were found in a nearby compound.

NATO also said a U.S. troop was killed Tuesday by a roadside bomb in Helmand province. No other details about the death were released.