KABUL: Afghanistan on Friday banned the use of a fertilizer chemical also used to make bombs, giving farmers and other holders a month to turn in their supplies.

President Hamid Karzai's office issued a decree banning the use, production, storage, purchase or sale of ammonium nitrate and giving Afghans 30 days to turn in any supplies to authorities.

The decision was made after an investigation showed that militants had used the chemical in a series of bombings, according to a statement.

NATO-led forces already have been confiscating the chemical compound, urging farmers to use fertilizer containing urea nitrate instead. Ammonium nitrate fertilizer has been used to make about 95 percent of the bombs in Afghanistan, according to the military think tank Globalsecurity.org.

The government also ordered training for police and border customs house workers to detect the chemical.

It warned violators who fail to turn in supplies of ammonium nitrate will face court action.

Afghanistan's government gave U.S. and allied forces permission to confiscate ammonium nitrate in September and troops have been seizing huge quantities of fertilizer in return for compensation for the holder.

A joint force of NATO and Afghan troops found a truck carrying 10 tons of suspect fertilizer in the southern province of Kandahar earlier this month.